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Eggs in Cold Storage 



THEORY AND PRACTICE IN PRESERVING EGGS BY RE- 
FRIGERATION. DATA, EXPERIMENTS, HINTS ON 
CONSTRUCTION, ETC., FROM PRACTICAL 
EXPERIENCE/ WITH ILLUSTRATIONS. 



MADISON COOPER. 




Chicago : 

H. S. RICH & CO. 

1899. 



38859 



Copyrighted 1898, 1899 
By MADISON COOPER. 



FW©#a*iEs *4oeiveo, 




PRESS 01? 

ICK AND REFRIGERATION, 

CHICAGO. 






PREFACE. 

IN the interest of a better understanding- and dissem- 
ination of knowledge on the cold storage of eggs, 
the writer has communicated with quite a large num- 
ber of individuals and companies, asking their ideas 
and requesting that they give full answers to a printed 
list of questions sent them. Although, at first, the 
replies were rather slow in coming in, the total result 
of these letters has been most gratifying; nearly one- 
half acknowledging receipt of the inquiry, and more 
than one-half of this number giving fairly full replies 
to the questions submitted. Considering the fact 
that the inquiries were regarded by some as being of 
a rather personal nature, the proportion of managers 
sending full replies is large. Several gentlemen were 
frank enough to say that personal considerations pre- 
vented them from giving any information; others 
gave guarded or partial repli&s,:: In the main, how- 
ever, storage men have been willing to give informa- 
tion and exchange ideas. 

The list of inquiries sent out covers the subject 
very thoroughly, and divides it into six different 
parts, with three separate questions relating to each. 
To the data so cheerfully furnished by others is added 
information from thewriter's experience and practice, 
with such explanation of theory and practice as may 
seem necessary to a clear understanding of the prin- 
ciples of successful egg refrigeration. It is hoped 
that those who are new to the business may obtain 
valuable information from these collected data, and 
that those with experience may derive some benefit 
in the way of a review, and possibly pick up some 
new ideas as well. 

A large portion of the matter contained in these 



4 PKKFACE. 

pages appeared in Ice and Refrigeration as a series 
of articles entitled: "Eggs in Cold Storage." The 
present book is printed for the purpose of putting 
the matter in permanent form, believing that those 
who have followed the orig-inal articles would find it 
convenient for future reference. While the present 
book has many shortcomings, and there is no doubt 
room for the addition of much information, reliable 
data, and the results of extended observations and 
tests, there has not heretofore been anything like a 
complete write-up of the subject; and in consideration 
of this fact the reader is asked to be liberal in his 
criticism. 

If any errors or lack of details are noted, the 
author would gladly acknowledge and explain the 
points at fault if his attention is called toany. No other 
object has been in mind in writing these articles than 
a furtherance of scientific knowledge on the subject 
of refrigeration as applied to the preservation of per- 
ishable products, and the great assistance rendered 
by those who have written painstaking replies to the 
list of inquiries is hereby acknowledged. The com- 
bination and comparison of information are beneficial, 
and if those who have further data or records of tests 
will only put them before others in their line of busi- 
ness, no loss will be sustained by the individual giv- 
ing the information, while much general good will 
result. 



INTRODUCTION. 

THE value of the eggs placed in cold storage for 
preservation is estimated at about $20,000,000 
annually for the United States alone. Considering 
the importance the industry has already attained, its 
rapid growth and future outlook, the amount of ac- 
curate information available to those engaged in the 
business seems very meager. The difficulties to be 
overcome, the skill required. and the importance of a 
well designed structure are not usually explained by 
those interested in promoting new enterprises in this 
line, and consequently not appreciated by those mak- 
ing the investment. Financial disaster has over- 
taken many large companies who have erected costly 
refrigeratingwarehouses; those which have succeeded 
have been forced to install new systems, make expens- 
ive changes, and make a thorough study of the prod- 
ucts handled. The experience of nearly all has been 
emphasized at times by heavy losses paid in claims 
made by customers for damage to goods while in 
storage, or the necessity of running a large house 
while doing a very small business. Those about to 
become interested in the business may find food for 
thought in the above, and the history of a dozen 
houses, in different localities,willbegood information 
for would-be investors. 

The scarcity of knowledge on the subject in hand, 
while being partly the result of the half developed 
state of the art until very recently, is also very 
largely owing to narrow-mindedness on the part of 
some of the older members of the craft, who have 
largely obtained their skill by years of experience 
and study, some of them having expended large sums 
on experimental work. The same experiments have 



6 INTRODUCTION. 

perhaps been made before, and are of necessity to 
be made again by others, simply because the first 
experimenter would not give other people the benefit 
of his experience, It seems at this stage in the de- 
velopment of refrigeration, that the improvements to 
be made during the next twenty years will be of very 
much less importance than those made during the 
twenty years just ending; trade secrets, so jeal- 
ously guarded by some, must disappear, as they have 
in other branches of engineering. Storage men have 
been obliged to work out their own salvation in stor- 
ing problems, sometimes sending their most difficult 
points to be answered through the columns of Ice and 
Refrigeration, and, perhaps, comparing ideas with 
those of their personal friends in the same line of 
business. It is to be observed that the most pro- 
gressive and up-to-date manufacturing concerns in 
the United States to-day are giving their contempo- 
raries every opportunity of observing their methods, 
and are very willing and anxious to talk over matters 
pertaining to their work, from an unselfish stand- 
point. So, too, the successful cold storage of the 
future will be sure to make " visitors welcome." 

In anything which will appear in these articles, it 
is not the writer's intention to convey the idea that 
any mere theoretical knowledge, which can be ac- 
quired by reading and study, or even by an exchange 
of ideas in conversation, can take the place of practi- 
cal observation in actual house management; but 
there are applications of well known natural laws, 
which are not generally understood by storage men, 
and their progress is handicapped from lack of this 
theoretical knowledge. The two following illustra- 
tions, bearing on temperature and ventilation, are 
among the common errors made in practice, yet easily 
understood when studied and tested: Some storage 
houses have formerly held their egg rooms at 33° F., 
fearing any nearer approach to the freezing point of 



INTRODUCTION. / 

water (32° F.), thinking - the eggs would freeze. A 
simple experiment would settle this point, g'iving the 
exact freezing" temperature, as well as the effect of 
any low temperature on the egg" tissues. Again, 
others have thought to ventilate by opening" doors 
during warm weather. It never happens that storage 
rooms can be benefited by this treatment at any time 
during the summer months, and only occasionally 
during spring and fall. The dew point of outside air 
is rarely below 45° F. during summer, and when 
cooled to the temperature of an egg room, moisture 
will be deposited on the goods in storage, causing a 
vigorous growth of mildew. 



m 



r -A 






EGGS IN COLD STORAGE. 



CHAPTER I. 

TEMPERATURE. 

TEMPERATURE is selected for first considera- Temperature 
. . , . 1 P ~ . . moreimportant 

tion, as it is the primary element of refrigeration, than any other 

. .. , .. . . ~ condition. 

and more important than any other condition. Correct 
temperature alone, however, will not produce success- 
ful results, anymore than a good air circulation, or cor- 
rect ventilation, would give good results with a wrong 
temperature. This applies more especially to egg re- 
frigeration, some products requiringonly alow temper- 
ature for preservation. The common impression of 
cold storage is what the name implies — simply a build- 
ing in which the rooms may becooled to a low degree 
as compared with the outside air. Even those who 
build, sell and erect refrigerating machinery and appa- 
ratus often show either gross carelessness or ignor- 
ance of the requirements of a house which w 7 ill produce 
successful results. After a careful examination of 
some of the recently constructed houses, supposed to 
be strictly modern and up to date, the writer gets the 
impression that the architects regard temperature 
as the only requisite for perfect work. Some of theunskiiifuiiy 
rooms in these new houses are simply insulated and egg rooms. 
fitted with brine or ammonia pipes, the location of the 
coils having no attention whatever, being placed, in 
most cases, in convenient proximity to the pipe main, 
and in one or two, instances, the top pipe of the cooling 
coils was fully two feet from the ceiling. The ne- 
cessity of providing for air circulation seemed not 
worthy of consideration, to say nothing of the lack of 
anything like an efficient ventilating system. 

Questions regarding the correct temperature of Opinions 

i 1 ii n<- regarding 

egg rooms have been asked repeatedly of storage correct " 

i -i ' ., . .. , ', .. , temperature. 

men who have been in the business long enough to be 



10 



EGGS IN COLD STORAGE. 



Questions 
relating - to 
temperature. 



Figures 
received relat- 
ing - to correct 
temperature. 



looked to for advice, the same person, perhaps, 
giving- a different answer, from time to time, as his 
ideas changed. The query has also been asked and 
answered through the columns of Ice and Refrig- 
eration a number of times. At present, however, 
there is no temperature on which a large majority of 
persons can agree as being- rig-ht, and as giving- su- 
perior results to any other. The claims made by the 
advocates of different temperatures will be consid- 
ered, to determine, if possible, what degree is giving 
the best results in actual practice. 

The three questions relating to temperature were 
written to draw out opinion as to the right tempera- 
ture, the lowest safe temperature, and what delete- 
rious effect, if any, the egg sustained at low tempera- 
tures, which did not actually congeal the egg meat. 
The three temperature queries were: 

First. — At what temperature do you hold your 
rooms for long period egg storage? 

Second. — What temperature do you regard as the 
lowest limit at which eggs may be safely stored? 

Third. — What effect have you noticed on eggs held 
at a lower temperature? 

All the replies received contained answers relative 
to temperature, and by a very small majority 32° F. 
is the favorite temperature for long period egg 
storage. Some few, 33° F. and 34° F., with a few 
scattering ones up to 40° F. Under the freezing 
point, none recommended a temperature lower than 
28° F., and for a very obvious reason, this being near 
to the actual freezing temperature of the albumen of 
a fresh egg. A very respectable minority say a tem- 
perature ranging from 30° F. to 31° F. is giving them 
prime results; and several recommend 30° F. straight, 
and say they should go no lower. In recent years 
there has been a decided tendency among storage 
men to get the temperature down near the safety 
limit, but many houses are so poorly equipped that 



KGGS IN COLD STORAGE. 11 

they are unable to maintain a uniform low tempera- 
ture below 33° F., without danger of freezing eggs 
where they are exposed to the flow of cold air from 
coils. A house must be nicely equipped to maintain 
low temperatures with safety. More houses would 
use temperatures under 32° F., were they able to, ^ n a d r e d n g wer 
without danger to the eggs. A very successful east- ^™P^ature 
ern house issued a pamphlet in 1892. At that time 
they maintained a temperature of 32° F. to 34° F. in 
their rooms. In sending- out this little book during 
the winter of 1897-98 a postscript was added, as fol- 
lows: "This pamphlet was published in 1892, when 
our plant was started. Since that time all first- 
class cold storage houses have lowered their temper- 
atures materially." No better illustration than this 
can be cited to show the tendency of the times. 
These people now use a temperature of 30° F. for 
eggs. 

Most of the replies received contained answers to Replies to 

'-vt i i • querv No. 2. 

question JNo. 2, and the greater portion state this as 
being about 2° F. lower than that recommended for 
long period storage. It is presumed that these two 
degrees are allowed as leeway, or margin of safety, 
for temperature fluctuations. Some state that eggs 
cannot be safely held below 32° F., but give no reason 
why, while two or three say a temperature of 27° F. 
will do no harm to eggs in cases. One reply states 
that eggs held in cut straw at 25° F. for three months 
showed no bad symptoms. It has never been made 
clear how the package can be any protection against 
temperature, when the temperature has been contin- 
uously maintained for a length of time sufficient to 
allow the heat to escape; and we know that eggs will 
positively freeze at 25° F., as proven by experiments 
mentioned in another paragraph. 

The answers to question No. 3 were few in num- Replies to 
ber, but cover a wide range. The scarcity of data on queri 
this point indicates that few have experimented with 



12 EGGS IN COLD STORAGE. 

eggs at temperatures ranging- from 25° F. to 30° F. 
Some say: "Dark spot, denoting germ killed"; others, 
"white gets thin"; others, "eggs will decay more 
quickly"; or, "they will not 'stand up' as long when 
removed from storage." It is also claimed that "yolk 
is hardened or 'cooked' when temperature goes below 
32° F." Some answers state a liability of freezing if 
eggs are held in storage at a temperature below 32° F. 
for any length of time. 
theadvoctte S by As f ar as possible, we will dig out reasons for the 
tempCTatures.™ claims made by advocates of both high and low tem- 
peratures, both having equal consideration. Taking 
29° F. or 30 c F. and 38° F. or 40° F., as representing 
the lowest and highest of general practice, we will see 
what is claimed by each; and also the faults of the 
other fellow's way of doing it, as they see it. Those 
who are holding their egg rooms at 40° F. say it is 
economical, that the eggs keep well, that the consis- 
tency of the egg meat is more nearly like that of a 
fresh egg after being in storage six months, than if 
held at a lower temperature. As against a low tem- 
perature they say: A temperature of 30° F. is expen- 
sive to maintain; the yolk of the egg becomes hard 
and the white thin, after being in store for a long 
hold ; and that when the eggs are taken from storage 
in warm weather it will require a longer time to get 
through the sweat than if held in storage at a some- 
what higher temperature, resulting in more harm to 
the eggs. Some claim that the keeping qualities are 
impaired by holding at a temperature as low as 30 c F., 
and others note a dark spot, or clot, which forms in 
the vicinity of the germ, when eggs are held below 
33° F. Against this formidable array of claims, the 
low temperature men have some equally strong 
ones, although fewer in number. They say: There 
is very much less mildew, or must, at 30° F. than at 
temperatures above 32° F.; the amount of shrinkage 
or evaporation from the egg is less; an egg can be 






EGGS IN COLD STORAGE. 13 

held sweet and reasonably full at this temperature 
from six to eight months. This last claim is a broad 
one, and very few houses are turning- out egg's an- 
swering to this description. 

The following, relating to high temperatures, is man-^oplnion 
quoted from a letter written by one of the best posted temperatures. 
men in the business, who has spent much money and 
time on experiments, and studied the question for 
years. He says: "A temperature of 40° F. is very 
good for three months' holding, but if they run over 
that, it is more than likely the eggs will commence to 
cover with a white film, which grows the longer they 
stand, and finally makes a musty egg.^ This gen- 
tleman advocates a temperature of 30° F. for long 
period holding. It should be noted that the high 
temperature men ignore entirely the effect of high 
temperatures on the growth of this fungus, spoken of 
above as a white film. The worst thing about most 
storage eggs is the taste caused by this growth, 
(usually called mildew or mold), which results in what 
is commonly called a musty egg. To enable us to 
understand the validity of these claims made by the 
30 c F. people, it will be necessary for us to ascertain 
the conditions which are favorable, and also the con- 
ditions which are unfavorable for the propagation of 
this growth of fungus, which has given storage men 
so much trouble, ever since cold storage was first 
used for the preservation of eggs. 

Heat and moisture are the two conditions leading- causes operat- 

° ing- to produce 

to its rank growth, and the opposite — dryness and cold a growth of 

r r J fungus on eggs 

— will retard or stop the growth entirely. In moist, in cold storage, 
tropical countries many species of this parasite grow, 
while in the cold, dry regions of the north its exist- 
ence is limited to a single variety. The causes lead- 
ing to a growth of the fungus on the outside of an egg 
are not far to seek. It feeds on the moisture and 
products of decomposition which are being constantly 
given off by an egg, from the time it is first dropped 



14 EGGS IN COLD STORAGE. 

until its disintegration, unless immersed in a liquid, 
or otherwise sealed from contact with the air. This 
evaporation not only takes moisture from the egg, 
but carries with it the putrid elements from the egg 
tissue, resulting from a partial decomposition of the 
outer surface of the egg meat. Conditions of excess- 
ive moisture and the presence of decaying animal or 
vegetable matter, together with a moderate degree of 
heat, are essential to the formation of fungus of the 
species which are found growing on eggs in cold 
storage. As the heat and moisture are increased, the 
growth of fungus will be proportionate. Furthermore, 
we all understand that heat hastens decomposition, 
and the partial decomposition of an egg results in a 
growth of the fungus, as before explained, when con- 
ditions of temperature and humidity are favorable. If 
the temperature is low, this growth is slow; for in- 
stance, if eggs are held at a temperature of 30° F. in 
an atmosphere of given humidity, the growth of fungus 
is less rapid than if held at any temperature higher, 
with the same per cent of humidity. As our subject 
merges into humidity here, the reader is referred to 
what is said under this head in another chapter. 
someexperi- Returning to the objections urged against low 

ments on the ... ^ , ^ • 1 • 1 

freezing point temperatures, we will see what damage is claimed 
from the use of a temperature of 29° to 30° F. The 
objections are: Liability of freezing; germ is killed; 
white becomes thin; yolk is hardened, and eggs will 
not keep as long when removed from storage. Some 
interesting results are obtained from experiments 
made by the writer. Half-rotten or "sour" eggs 
freeze at temperatures just a trifle under 32° F. 
Fresh eggs freeze at 26° to 27° F. In testing eggs 
which had been held in storage for several months, it 
was noted that the freezing point had been depressed 
from 1° to 2° F. An egg which is leaky will freeze at 
2° to 3° higher temperature than one which is sound, 
probably owing to the evaporation resulting in a lower 



EGGS IN COLD STORAGE. 15 

temperature. The freezing- point of eggs, as above, 
is understood as being- the degree at which they begin 
to form ice crystals inside. Of the replies received 
touching on the freezing point of eggs, nearly all agree 
with above experiments. The " dead germ " theory Dead germ 
the writer has never been able to locate in fact, hav- 
ing never seen anything of the kind in eggs held as 
low as 28° to 29° F. for several weeks' time; nor in 
eggs held at 30° F., or a trifle under, through the sea- 
son. As only two or three mention having noted this 
result, it would seem that some local conditions, and 
not low temperature, were responsible. 

The matter of the white becoming thin when eggs {^^atures 
are held at low temperatures has some bearing; in oneggs - 
fact, any egg held at a cold storage temperature for 
a long carry will show this fault, to a certain extent, 
especially if cooled quickly when stored, or warmed 
suddenly when removed from storage. With refer- 
ence to the above, it is the writer's opinion that a dif- 
ference of 4° to 6° F. in carrying temperature will 
not be noticeable in its effect on the albumen of an 
egg; and as to the effect of a low temperature 
on the egg yolk, it has been demonstrated that 
any temperature, which will not actually congeal the 
albumen, will not harm the yolk of an egg. There 
is a slight tendency, in this case, to a similar effect to 
that produced by a low temperature on cheese; that 
is, causes it to become " short " or crumbly. 

In regard to a low temperature egg not keeping as 
long when removed from storage, it has been the 
experience of the writer that no difference was noted 
between eggs put out from storage and the current 
receipts of fresh eggs, so far as any complaint or 
objection was concerned, the eggs being shipped in 
all directions, in all weathers and subject to many 
different conditions. A test was also made, by placing a test showing 

j. v. j j- -i • -i i 1 , •-•• keeping quali- 

tnree dozen of eggs, which had been carried in storage ties of eggs 

, - __..,, _ _ _ „ _ held at low 

at a temperature of 28^ F. to 30^ F. for five months, temperature. 



16 EGGS IN COLD STORAGE. 

in a case along - with three dozen fresh eggs. After 
three weeks no pronounced change was noted in 
either, both showing considerable evaporation as a 
result of exposure to the dry fall atmosphere. They 
were exposed to the temperature of the receiving 
room, fluctuating from 50° F. to 80° F. The eggs 
from storage went through a "sweat," while the fresh 
were not subjected to any such trial. As most eggs 
are consumed inside of three weeks after being re- 
moved from storage, this would seem like a good 
practical test of the vitality of a low temperature 
egg. A mere matter of economy between holding "a 
room at 40° F. and 30° F., while readily appreciated 
and admitted, seems of very small importance, when 
a positive advantage can be obtained by carrying eggs 
at the lower temperature; and a difference of 4° F. to 
5° F. would be scarcely worth considering. 
Low tempera- An advantage of low temperature, not vet men- 

ture prevents x J 

"spot" rotten tioned, is the increased stiffness, or thickness, of the 

eggs. 

white of the egg while in storage, holding the yolk in 
more perfect suspension. When eggs are held at a 
temperature of 36° F., or above, for any period longer 
than four months, the yolk has a decided tendency to 
rise and stick to the shell, causing rotten eggs, known 
as "spots." It is usually understood that the yolk set- 
tles; but, being of a fatty composition, it is lighter than 
the albumen, and rises instead. If the albumen is 
maintained in a heavy consistency, the yolk is retarded 
from rising, and held in a more central position. It 
was long a practice with storage men to turn eggs at 
least once during the season, to prevent the above 
trouble, and some recommend it even now; but the 
practice has been generally abandoned with the ad- 
vent of low temperatures for egg storing. 
Putting- eg-g-s in When eggs are put in cold storasre they should not 

and removing- o o r o j 

from storage, be CO oled rapidly. The effect on the egg tissues is 
bad — they should have time to rearrange themselves 
to the changed temperature. This is especially true 



EGGS IN COLD STORAGE. 17 

where eggs are placed in storage in extreme warm 
weather. Sudden warming is also detrimental to the 
welfare of an egg, for a similar reason to above. The 
most noticeable effect of either is a thinned albumen. 
If this process of cooling and warming could be prac- 
ticed carefully (which is not always practicable com- 
mercially), a well kept storage egg would come out of 
storage with nearly the same vitality it had when fresh. 



CHAPTER II. 



Data available 
on humidity 
practically 
nothing-. 



Evaporation 
and mold can 
be prevented. 



Questions 
relating 1 to 
humidity. 



HUMIDITY. 

INFORMATION on the subject of humidity, as 
applied to the cold storage of eggs, is very meager. 
Not more than a dozen of the replies received in 
answer to the lis t of inquiries sent out contain infor- 
mation on the three queries under the head of hu- 
midity. Considering the amount of talk we have all 
heard, with dry air as a subject, this scarcity of knowl- 
edge is rather surprising. Those who have had ex- 
perience with cold storage work and the products 
handled are well aware that an essential for good re- 
sults in egg refrigeration is a dry atmosphere in the 
egg room ; but just how dry, very few are able to give 
even an approximate estimate. Very likely if a cold 
storage man is asked in regard to it, he will reply 
that an egg room should be "neither too moist nor 
too dry." What this "happy medium " is, that will 
not shrink or evaporate the eggs badly, and yet keep 
down the growth of fungus to a minimum, is what all 
are striving for, and very few have the means of 
knowing when this point is reached. A few years 
ago a prominent commission man, in conversation 
with the writer, speaking of storage eggs, said : 
"You storage men are between the devil and the 
deep sea. You always shrink 'em or stink 'em"; 
meaning that eggs which were held long in storage 
would show either a considerable evaporation or a 
radical " musty " flavor. To some extent this is true, 
but with a penetrating circulation, careful ventilation 
and a judicious use of absorbents (all of which will 
be considered under their proper heads) egg can be, 
and are, turned out of storage without this strong, 
foreign flavor, and with little evaporation or shrinkage. 
The questions relating to humidity were written 
with a full understanding of the scarcity of informa- 
tion on the subject, and were designed to locate, if 

18 



KGGS IN COLD STORAGE. 19 

possible, those who were making- tests of air moist- 
ure, and get opinions on the correct humidity for a 
given temperature. The following are the queries: 

First. — What tests, if any, have you made of the 
dryness or humidity of your egg rooms? 

Second. — What per cent of air moisture do you find 
gives the best results at the temperature you use? 

Third. — What instrument do you use for testing 
air moisture? 

Questions 1 and 3 are practically the same, the 
latter being written simply to make the query more 
plain and indicate whether an instrument or some 
other test was used for determining air moisture. 
Four houses reporting are using the dry and wet bulb 
thermometers ; the others are using hygrometers of 
French or German make. 

The answers to question 2 vary greatly ; some Replies reiat- 

71 . . in S to correct 

also giving the actual testing humidity of their rooms humidity, 
and their opinion of a correct degree as well. From 
70 to 80 per cent of humidity is the test of nearly all 
reporting, and of the rooms tested by the writer, 
nearly all show a similar humidity, with one occasion- 
ally going as high as 85 per cent, and some as low as 
65 per cent. Two answers recommend a humidity 
of 65 per cent, and one a humidity of 60 per cent, 
with a temperature of 30° F. to 32° F. Others hold 
that their testing humidity of 70 to 80 per cent is 
correct. The matter of correct humidity will be dis- 
cussed further on. 

The humidity of a room depends on the season to^^^ s 
a moderate extent, and the condition of the room, as humidity. 
regards ventilation, in some cases. In late fall or 
winter, especially, if air is taken directly into the 
room from the outside, the humidity will be low. As 
cool weather approaches, the tendency is for the 
humidity to rise, and unless kept down by ventilation 
or by the use of absorbents, serious consequences are 
sure to follow. 



20 



EGGS IN COLD STORAGE. 



What relative 

humidity 

sisrnifies. 



Quoted from 
"Instructions 
to Weather 
Observers." 



To enable us to thoroughly understand the mean- 
ing- of relative humidity, as it is called, we will study 
a few extracts from " Instructions to Voluntary Ob- 
servers, " issued by the Weather Bureau at Washing- 
ton, D. C. Humidity is considered on a decimal scale, 
with 100 the saturation point of the air, at which it 
will hold no more water vapor, and the point at 
which air contains no moisture whatever. The vari- 
ous percentages between these points is a degree of 
humidity relative to these two extremes, or relative 
humidity- The quotations below are not contained 
in the recent issue of instructions, but are from the 
issue of 1892, which is now superseded by that of 1897. 

WATER VAPOR IN AIR. 
The air contains vapor of water, transparent and color- 
less like its other gaseous components. It only becomes visible 
on condensing- to fog- or cloud, which is only water in a fine 
state of division. The amount is very variable at different 
times, even in the vicinity of the ocean. The amount of moisture 
that can exist as vapor in the air depends on the temperature. 
There is a certain pressure of vapor, corresponding to every 
temperature, which cannot be exceeded ; beyond this there is 
condensation. This temperature is called the temperature of 
saturation for the pressure. When the temperature of the air 
diminishes until the saturation temperature for the vapor con- 
tained is reached, any further fall causes a condensation of 
moisture. The temperature at which this occurs is called the 
dew point temperature of the air at that time. The less the 
quantity of moisture the air contains, the lower will be the 
temperature of the dew point. For different saturation temper- 
atures, the weight of vapor, in grains, contained in a cubic 
foot of air is as follows: 



Temperature of 
Saturation, Degrees F. 


10 
20 
30 
40 
50 
60 
70 
80 
90 
100 



Weight in a 
Cubic Foot, Grains. 

0.56 
0.87 
1.32 
1.96 

2.85 

4.08 

5.74 

7.98 
10.93 
14.79 
19.77 



EGGS IN COLD STORAGE. 21 

The air is never perfectly saturated, not even when rain 
is falling-; neither is it ever perfectly dry at any place. Rela- 
tive humidity expresses relative amount of moisture in the air 
only as long- as the temperature of the air remains constant. 
For this reason relative humidity is an imperfect datum. At a 
low temperature, even a high relative humidity represents a 
very small amount of vapor actually in the air, while a low 
relative humidity at a high temperature represents a great 
deal. 

The most important law relating- to above concise Law governing 

x _ " air moisture. 

statements, and one which, if carefully noted and 
applied, will make all work in humidity easily under- 
stood, is best expressed thus: The capacity of air for 
moisture is increased with its temperature* 

At a temperature of 40° F., air will hold in sus- 
pension more water vapor than at any lower tempera- 
ture (see table); and when the difference is as much 
as 10° F., the difference in the amount of moisiure 
the air will hold is very considerable. To illustrate: 
Air which is saturated with moisture at 30° F.-_, when 
raised in temperature to 40° F., then holds but 68 per 
cent of its total capacity. 

Under the head of "Temperature," it is stated y ari .ation of 

r ' humidity with 

that: "If eggs are held at a temperature of 30° F. in temperature 

00 r illustrated. 

an atmosphere of a given humidity, the growth of 
fungus is less rapid than if held at any temperature 
higher, with the same per cent of humidity. Refer- 
ring again to the table, we see that a cubic foot of air, 
when saturated at a temperatureof 40° F., contains2.85 
grains of water vapor, while at 30 G F. it contains but 1.96 
grains, or only about two-thirds as much as at 40° F. 
The same holds true with any relative humidity, the 
same as when the air is saturated. . Take, for instance, 
air at a temperature of 40° F., with a humidity of 75 
per cent, then a cubic foot of air holds 2.14 grains of 
water vapor per cubic foot; and at a temperature of 

* Strictly speaking-, air has no capacity for moisture, the water vapor being 
simply diffused through the air, after the nature of a mechanical mixture. For 
all practical purposes, we may regard it as being absorbed by the air, and it is 
usually so treated. 



22 EGGS IN COLD STORAGE. 

30^ F., with the same relative humidity, it would hold 
but 1.47 grains. This great difference in the amount 
of moisture contained in the air at different temper- 
atures, and still having - the same relative humidity, 
has as radical an effect on the growth of fungus 
as does the difference in temperature. This is no 
mere theory, as the writer has demonstrated it, to his 
own satisfaction, at least, during several seasons' 
observation. If it is hoped to keep down the growth 
of fungus in a temperature of 40° F. by maintaining an 
Result of too atmosphere with a lower relative humidity, the result 
rcxL anegg i s a badly evaporated egg, which loses its vitality and 
value very rapidty when held in storage for a term 
exceeding three or four months; the white becomes 
thin and watery, with a strong tendency to develop 
"spot" rotten eggs. As the fullness or absence of 
evaporation is of only secondary consideration to their 
sweetness, when eggs are tested by buyers, it is 
necessary to prevent this trouble if the eggs turned 
out from storage are to be considered first-class. 
correct relative From the foregoing it seems clear that to turn out 

humidity not ° & 

kno"vn tely sweet eggs at a temperature of 40° F. it is necessary 
to maintain a lower relative humidity than at any tem- 
perature lower, and the result cannot fail to be as de- 
scribed. The writer has already given a summary of 
the replies to the questions relating to humidity, which 
are few in number, and not very complete. A little 
is better than nothing, however, and by comparing 
his own data with the results obtained by others, and 
paying careful attention to their opinions, the follow- 
ing table of correct humidity for a given temperature 
in egg rooms has been compiled. There are no data on 
the subject in print, so far as known, and no claim for 
absolute accuracy is made in presenting this first 
effort in that direction, but as the figures are taken 
from actual results, no great mistake can be made by 
depending on them. The percentages of humidity 
given are modified, to some extent, by the intensity 



EGGS IN COLD STORAGE. 23 

and distribution of the air circulation employed. (See 
Chapter III on "Circulation.") 

Correct Relative Humidity for a Given Temperature 
in Egg Rooms. 

Temperature Relative Humidity, Humidity table 

in Degrees F. Per Cent. f or e o-rr rooms. 

28 80 

29 78 

30 76 

31 74 

32 71 

33 • 69 

34 67 

35 65 

36 62 

37 60 

38 58 

39 56 

40 53 

There are two kinds of instruments in use for de- Hygrometers. 
termining humidity, hygrometersand psychrometers. 
The hygrometer depends on the expansion and con- 
traction of some substance, as a human hair, in the 
presence of more or less moisture in the air. The 
hair used is fastened at one end, the other end passing 
around a pulley, to which is fastened a pointer, which 
moves over a graduated arc as the hair changes its 
length. The scale reads from to 100. The chief 
advantage of these instruments is that results are 
obtained at once, the reading corresponding to the 
percentage of saturation or relative humidity; but 
these instruments are affected by changes of tem- 
perature, and shocks or vibration materially affect 
the reading. Further, they are more expensive in 
first cost, and not so convenient to use, as they must 
hang for some time in the room to be tested, while 
with the sling psychrometer, described in another 
paragraph, an observer can pass from room to room, 
getting observation in less than two minutes in each 
room, needing but one instrument and making all 
observations at practically the same time. 

A psychrometer is simply two thermometers Psychrometers. 
mounted on a frame ; the bulb of one being covered 



24 



KGGS IN COLD STORAGE. 



Stationary 

psychrometer. 



Sling- 

psychrometer. 



with muslin so as to retain a film of water surround- 
ing- it. The working- of this instrument depends on 
a law which may be roughly expressed, as "evapora- 
tion carries off heat." The evaporation of water from 
the bulb incased in muslin, known as the wet bulb, 
cools it somewhat, depending on how dry the air sur- 
rounding it may be. The difference between the 
reading of the wet bulb thermometer and the reading 
of the dry bulb thermometer, when compared with 
reference to a prepared table, gives the relative 
humidity of the air at the time of making the observa- 
tion. Psychrometers are of two kinds, stationary 
and sling. 

The stationary psychrometer is essentially like 
the sling psychrometer, both depending on the same 
principle. The sling instrument is more compact 
and provided with a handle for whirling, while the 
stationary instrument is intended to be fastened 
against the wall, or on a post, the muslin covering the 
wet bulb being connected by a porous cord with a 
reservoir of water, to keep the supply of water con- 
tinuous. This is essential, as it takes some little 
time to obtain a correct reading with this pattern of 
instrument. For this reason it is open to the same 
objections as the hygrometer. Also, after short use 
the muslin covering the wet bulb, and the cord feed- 
ing water to it, become clogged with solid matter and 
fungous growth affecting its accuracy. At any tem- 
perature below 32° F. this instrument is useless, as 
the water will freeze in the cord supplying the mus- 
lin on the wet bulb, and the muslin becomes dry in 
consequence. 

For practical, accurate and quick results at any 
temperature there is no instrument so reliable and 
convenient as the sling psychrometer, preferably of 
the pattern known as Prof. Marvin's improved psy- 
chrometer, shown in the illustration. This is a 
standard Weather Bureau instrument, and when used 



EGGS IN COLD STORAGE. 



25 




?J 



SLING 
PSYCHRO 



in connection with the tables of hu- 
midity published by the bureau, any 
needed results may be obtained with 
a fair degree of accuracy. The sling- 
psychrometer, as illustrated, consists 
of a pair of thermometers mounted 
on an aluminum plate, one higher 
than the other, the lower having its 
bulb covered with a small sack of 
muslin. At theitop, the frame or plate 
supporting the thermometers is pro- 
vided with a handle for whirling, this handle 
being connected by links to the plate, and 
provided with a swivel to allow of a smooth 
rotary motion. The bulb of the lower ther- 
mometer is wet at the time of making an ob- 
servation, the muslin serving to retain a film 
of water, surrounding and in contact with 
what is known as the wet bulb of the psy- 
chrometer. The muslin should be renewed 
from time to time, as the meshes between the 
threads will gradually fill with solid matter 
left by the evaporation of the water and the 
natural accumulation of dust from the air. 
The muslin in this condition will neither ab- 
sorb nor evaporate the water readily. 

To make an observation dip the muslin Directions for 

A using- the sling- 

covered bulb in a small cup or other wide-P s y chrometer - 
mouthed receptacle containing v\ater. Whirl 
the thermometer for ten or fifteen seconds, 
then dip the wet bulb of the psychrometer 
into the water again. Whirl again for ten or 
fifteen seconds, stop and read quickly, read- 
ing the wet bulb first. Repeat once or twice, 
noting the reading each time. When two 
successive readings of the wet bulb agree 
very nearly, the lowest point has been 



meter, .reached. Dip the wet bulb only after the 



26 EGGS IN COLD STORAGE. 

first whirling-, as this is done only to make sure 
that the muslin is thoroughly saturated with water. 
If the water used is of nearly the same temperature 
as the room, correct readings are sooner obtained. 
If the psychrometer and water are at a much higher 
temperature than the air of the room, it will take a 
proportionately longer time to reach a correct read- 
ing-, but the accuracy will not be impaired, if sufficient 
time is allowed for the mercury to settle. It is very 
important that the muslin covered bulb should not 
become dry in the least; it should be saturated with 
water during the full time of observation. There will 
be no difficulty in getting accurate readings down to 
29° F., as indicated by the dry bulb. At about this 
temperature, and with the wet bulb at about 27° F., 
ice will form on the wet bulb and cause the psychro- 
meter to become somewhat erratic in its behavior.* 
sto ir ?n & siin d ^ * s difficult f° describe the proper movements 

psychrometer. f or whirling the sling psychrometer, a little practice 
being the best instructor. The handle is held in 
a horizontal position, the frame mounting the ther- 
mometers revolving around the pivot, after the man- 
ner of the weapon with which David slew Goliath, and 
from which our moisture-tester gets the easy part 
of its name. A high rate of speed is unnecessary, a 
natural, easy motion of the forearm or wrist being all 
that is required. When stopping the psychrometer 
the arm should follow the thermometer from the high- 
est point of the circle of rotation, whereby the radius 
of the path of the psychrometer is increased, and the 
momentum overcome. The stopping can be accom- 
plished in a single revolution, after a little practice. 
The psychrometer will come to rest very nicely by 
simply allowing the arm to stand still, but the final 
revolution will be quite irregular and jerky. 

* The writer is in receipt of a special report on this point, prepared by 
Prof. C F. Marvin, in charge of the instrument division of the Weather Bureau, 
and will gladly give any one having difficulty with the psychrometer at these 
temperatures information so far as he can; but the point involved is somewhat 
intricate, and so few are using temperatures as low as 29° F. that it is thought 
best to omit a discussion of this phenomenon. 



EGGS IN COLD STORAGE. 



27 



In making- observation in a storage room, the psy- ^ionf a°nd er 
chrometer should be held as far as convenient from p^^TOmeter 
the body, and toward the direction from which the 
circulation comes^the observer standing- to the lee- 
ward, as it were. In some cases it is necessary, or 
advisable, to step slowly back and forth a few steps, 
and the observer should turn his head from the di- 
rection of the psychrometer, so his breath will not 
affect the reading. In reading a thermometer, read 
as quickly as possible, and do not allow the breath to 
strike the bulb. It is a common practice with the 
writer to hold his breath while reading a thermome- 
ter. It is unnecessary to caution against allowing the 
psychrometer to strike any object while whirling. 
In case it should, the observer will have $5 worth of 
experience, but no psychrometer. 

Relative Humidity, Per Cent. 



-r 














- 


Table of rela- 


s: 
>> 


Difference between the dry and wet thermometers (t—t 1 ). 


01 
■G 

i>. 

u 

Q 


tive humidity. 


Q 


0°.5 
94 


l°.0 
88 


1\5 
82 


2°.0 

77! 


2°.5 

71 


3°.0 

65 


3°.5 
60 


4°.0 

54 


4°.S 
49 


5°.0 
43 


5°.5 
38 


6°.0 
33 


28 


28 


29 


94 


89 


83 


77 


72 


66 


61 


56 


50 


45 


40 


35 


29 




30 


94 


89 


84 


78 


73 


67 


62 


57 


52 


47 


41 


36 


30 




31 


95 


89 


84 


79 


74 


68 


63 


58 


53 


48 


43 


38 


31 




32 


95 


90 


84 


79 


74 


69 


64 


59 


54 


50 


45 


40 


32 




33 


95 


90 


85 


80 


75 


70 


65 


60 


56 


51 


47 


42 


33 




34 


95 


91 


86 


81 1 
1 


75 


72 


67 


62 


57 


53 


48 


44 


34 




35 


95 


91 


86 


1 
82 


76 


73 


69 


65 


59 


54 


so 


45 


35 




36 


96 


91 


86 


82 


77 


73 


70 


66 1 


61 


56 


51 


47 


36 




37 


96 


91 


87 


82 


78 


74 


70 


66 


62 


57 


52 


48 


37 




38 


96 


92 


87 


83 


79 


75 


71 


67 


63 


58 


54 


50 


38 




39 


96 


92 


88 


83 


79 


75 


72 


68 


63 


59 


55 


52 


39 




40 


96 


92 


88 


84 


80 


76 


72 


681 


64 


60 


56 


53 


40 





The above short table needs no explanation fur- Weather 

■ l Bureau table. 

ther than has been already given. It will cover anv 
case in egg room observations. This table was not 
intended for cold storage work, being a part of the 
regular humidity tables published by the Weather 
Bureau. The full set of tables can be had by 



• 28 EGGS IN COLD STORAGE. 

addressing- the chief of the Weather Bureau, Depart- 
ment of Agriculture, Washington, D. C. They are 
published in pamphlet form, along with tables giving 
dew point temperatures. Observers must work out 
the small fractions for themselves, if they think 
necessary, but results within the limits covered by 
the table are near enough for present practical pur- 
poses. 

It is of no use to test for moisture unless having 
the ability to control it, any more than a thermometer 
would be of use unless the means of regulating tem- 
perature were at hand. Humidity can be controlled 
by ventilation and the use of absorbents, which are 
considered elsewhere. 



A 



CHAPTER III. 

CIRCULATION. 

vigorous and penetrating" circulation of air must circulation 

' essential. 



be maintained in a cold storage room for eggs if 
g-ood results are to be insured. The importance of 
this condition, as applied to eggs especially, is quite 
generally appreciated, and it is noticeable that the 
warehouses producing the most perfect work have 
scientific and carefully designed air circulating sys- 
tems. It is also a fact that a strong, searching circu- 
lation will do much to counteract defects in a cooling 
apparatus, or wrong conditions in the egg room in 
some other particular. In proof of this, the writer is 
familiar with a number of successful houses where 
prominence is made of the air circulating system 
only, some of the other conditions being neglected al- 
together, or. attended to in a perf unctory manner. 

Before going farther, it is best that we separate circulation not 

& & . . r ventilation. 

circulation from its tangle with ventilation. These 
two terms are quite commonly confused when applied 
to cold storage work. Circulation, as here discussed, 
applies to the motion of air within the storage room — 
air currents resulting from a difference in tempera- 
ture of the air in different parts of the room, or the 
result of mechanical force applied to the air by use of 
fans, blowers or exhausters. In distinction from cir- 
culation, ventilation means the renewal of the air of a 
storage room, either by forcing fresh air from the 
outside atmosphere into the storage room, or by ex- 
hausting the foul air from the room. Ventilation is 
not under consideration here, but will be taken up as 
a separate subject. 

The reason why a vigorous and well distributed circulation 

m J ° and moisture 

circulation of air in an egg room will give superior absorbing 

00 ° r capacity. 

results over a sluggish or partial circulation may not 
be readily apparent. A circulation of air is of benefit 
in combination with moisture absorbing capacity in 

29 



circulation. 



30 EGGS IN COLD STORAGE. 

the form of frozen surfaces or deliquescent chemicals. 
Stirring- up the air merely, as with an electric motor 
fan, without provision for extracting- the moisture, is 
of doubtful utility, and may, in some instances, prove 
positively detrimental, as it is liable to cause conden- 
sation of moisture on the goods, or walls of storage 
room, instead of its correct resting- place: the cooling 
coils and absorbents. Let us see how the circulation of 
air in a storage room operates to benefit its condition. 
pu°rYfiedby Under head of temperature, we have seen that 

the evaporation from an egg contains the putrid ele- 
ments resulting from a partial decomposition of the 
egg tissues, and that the air of a storage room carries 
them in suspension. It is probable that these foul 
elements are partly in the form of gases absorbed in 
the moisture thrown off from the egg; and if, there- 
fore, this moisture is promptly frozen on the cooling 
pipes, or absorbed by chemicals, the poisonous gases 
and products of decomposition are very largely ren- 
dered harmless. This is also true of the germs 
which produce mold and hasten decay, which are ever 
present in the atmosphere of a storage room, being 
carried to a considerable extent by the water vapor 
in the air, along with the foul matter of various kinds 
referred to. If the vapor laden air surrounding an 
egg is not removed and fresh air supplied in its place, 
the air in the immediate vicinity of the egg gets fully 
charged with elements which will produce a growth of 
fungus on its exterior, affecting and flavoring the in- 
terior — the flavor varying in intensity, depending on 
how thoroughly impregnated with fungus-producing 
vapor the air in which the egg is kept may be. In 
short, then, circulation is of value because it assists 
in purifying the air. It should be kept up so that 
the air may be constantly undergoing a purifying 
process to free it from the effluvia which are always 
being thrown off by the eggs, even at very low tem- 
peratures. It has been suggested that a brisk circu- 



EGGS IN COLD STORAGE. 31 

lation of air which will keep in motion the whole 
volume of air in the storage room will have a purify- 
ing influence independent of any moisture absorb- 
ing - capacity, but no satisfactory reason has been 
assigned. There may be such an influence opera- 
tive when the air is mechanically circulated. If so, 
there seems to be no scientific or practical explana- 
tion of it. 

Manv patents have been granted for improve- circulation in 

- r ° x natural ice 

ments in storage rooms or refrigerators using ice only refrigerators, 
for a cooling agent; house refrigerators, refrigerator 
cars and refrigerator buildings are represented in 
number about in order named. A large portion of the 
patents granted have been on claims for the improve- 
ment of circulation, and this is the keynote of what- 
ever success has been attained by the various sys- 
tems which use ice only for cooling. As any system 
of cooling whereby the air is caused to circulate in 
contact with melting ice is now quite generally re- 
garded as obsolete for the successful refrigeration of 
eggs for long period storage, a discussion of the 
merits of the various devices applied to this work 
will be omitted.* It may be said to their credit, how- 
ever, that the builders of ice refrigerators have orig- 
inated ideas on circulation which have been of much 
value to the present-day refrigerating engineers, and 
there are still those who may obtain good information 
from this source — the provision for circulation (or 
rather, lack of circulation) in a few of the new me- 
chanical cold storage houses being simply ridiculous. 

In the more progressive mechanically refrig-erated Ya -ll ou / . 

r ° jo methods in use 

houses there are a number of devices, which have f ? r promoting 

circulation. 

been introduced for assisting natural gravity air cir- 
culation, also the various modifications of the me- 

* The above must not be construed as condemning the use of ice as a 
refrigerant when rightly applied. The writer has in successful operation a sys- 
tem of gravity brine circulation, cooled by ice and salt, with which he will under- 
take to produce at moderate expense any possible results in refrigeration down 
to a temperature of 15 y F. 



32 



EGGS IN COLD STORAGE. 



Questions 
relating- to 
circulation. 



Answers to 
Query 1. 



chanical forced circulation system. Some of these 
will continue to gain favor because of the improved 
results obtained by their use. The main requisite 
in any air circulating- system is an ability to cause an 
equal distribution of the moving - air, as it comes from 
the moisture absorbing surfaces, forcing it uniformly 
to all parts of the room and compelling it to flow 
through and around the piles of stored goods. As a 
secondary consideration may be mentioned the equal- 
ization of temperature and humidity in all parts of the 
room. The writer is somewhat biased in favor of 
forced circulation, having developed a very complete 
system on this line, with some new features. Aside 
from a matter of economy of space and operation, 
the system employed matters little, if an effective cir- 
culation is produced. 

The questions bearing upon circulation contained 
in the list of inquiries sent out by the writer are as 
follows : 

Fi?'st.—hi piping your rooms what provision was 
made for air circulation? 

Second. — What difference in temperature do you 
notice in different parts of the same room? 

Third. — Do you use a fan or any kind of mechanical 
device for maintaining a circulation of air in the rooms? 

More answers were received on this subject than 
on the subject of humidity, but not exceeding one- 
third contained tangible replies to all three inquiries. 
Several of the answers confounded circulation with 
ventilation, as before alluded to. Question 1, in par- 
ticular, was badly neglected, indicating, no doubt, that 
no provision was made for circulation in a majority of 
cases. The common device in use for causing air to 
circulate more rapidly over the cooling coils, when 
they are placed directly in the room, is some form 
of screen, mantle, apron, false ceiling or partition, as 
illustrated in Figs. 3, 4 and 5. Many of these have 
been put up after the house has been in operation for 



EGGS IN COLD STORAGE. 33 

some time, and are very crude affairs, applied in all 
conceivable combinations with the pipe coils. In some 
cases canvas curtains, or a thin wooden screen, have 
been suspended under ceiling- coils with a slant to 
cause the cold air to flow off one side, and with sur- 
prising- improvement to the room, considering the 
simplicity of the device. Forced circulation with a 
complete system of distributing air ducts is coming 
into general use, as the meritsof this way of producing 
circulation are better understood and appreciated. 

Query 2 was answered more generally, but that Answers to, 
some of the answers were mere guesses, or state- 
ments made without testing, is very evident, as they 
state that no difference was noticed in different parts 
of the same room. With open piping or gravity air 
circulation, this is an impossibility — it is only possible 
with a perfectly designed forced circulation system. 
In contrast to this claim some answers state a differ- 
ence in temperature of as high as 4° F. to 5° F., but 
most answers show a difference of 1° F. to 2? F.; a 
few ^° F. to 1° F.; and, still others, as before stated, 
none at all. A marked variation of temperature in 
different parts of a room, while in most cases caused 
by defective circulation, is due sometimes partly to 
location of room as to outside exposure, proximity to 
freezing rooms, character of the insulating walls, etc. 
An egg room placed over a low temperature freezing 
room will show more variation between floor and 
ceiling than when located over another egg room, 
conditions being otherwise the same. Where this 
arrangement occurs, and the egg rooms are operated 
on a natural gravity air circulation system, eggs may 
be frozen near the floor, when a thermometer hanging 
at the height of a person's eyes would read 30° F. or 
above. Even with the very best insulation, the result 
of this very common arrangement is a defective cir- 
culation and more or less variation in temperature 
between floor and ceiling. 



34 



EGGS IN COLD STORAGE. 



Answers to 
Query 3. 



Gravity air 
circulation. 



In reply to Question 3, about a dozen state that 
they are using- some form of mechanical forced cir- 
culation. The advantages of this method will be 
discussed quite fully later on. About double this 
number are using the small electric fans. These 
also will be treated in the discussion of mechanical 
air circulation in another chapter. 

As air circulation is a somewhat neglected subject, 
and comparatively few have experimented enough to 
have positive opinions, based upon practical expe- 
rience, regarding the merits of different devices and 
methods, some of the more prominent and successful 
ones are illustrated and discussed in this article. 

In considering the following outlined arrange- 
ments of piping in the storage room and the various 
locations of screens, partitions, etc., in combination 
with the coils, for the purpose of separating the 
warm and cold currents of air (the one on its way 
upward from lower part of room to the top of 
cooling coils; the other downward from cooling- 
coil toward floor), the principle on which this 
movement of air operates should be noted, so 
that the underlying law may be understood. The 
cause of a circulation of air in a storage room with 
direct piping is a variation of temperature, which 
causes a difference in weight of the air in different 
portions of the room. The air in the immediate 
vicinity of the pipes is cooled to a lower temperature 
than in the balance of the room, causing it to drop 
toward the floor by reason of its greater specific 
gravity — what is designated as gravity air circulation. 
Just as long as the flow of the refrigerant is main- 
tained within the cooling pipes, the air will circulate 
by the action of gravity, the lighter warm air in top 
of room descending to replace the air in contact with 
pipes, which falls, as cooled, toward the floor. Should 
the refrigerant passing through coils be shut off, the 
cooling effect is checked, and as a result air circula- 



KGGS IN COLD STORAGE. 



35 



tion over the pipes ceases. This should make plain 
the fact that uniform temperatures in all parts of the 
room are not even an approximate possibility in any 
room depending- on natural gravity air circulation. It 
may also be observed that the eggs exposed to the 
flow of cold air near bottom of coils will stand in a 
dryer and colder atmosphere than those in top and 
center of room. 

Fig. 1 shows an outline sketch of piping suspended 9.^ ° verhead 
from the ceiling - of a room — the most unscientific way 
possible for a room to be piped, as it provides for no 



r 






zzzzzz 






V 



7^ 



F, e J. 



r 't 



zzzzzzzzzzzz 



9®h 



- J V 

+s - 



J 



^ZZZZZZu 



air circulation whatever. The only possible reason 
why air will circulate over pipes in this position is be- 
cause of the fact that the whole ceiling- is not covered 
by pipes, which allows of a partial circulation, as 
shown by the arrows. The volume of circulation in 
the lower half of room is practically nothing. It is 
larg-ely confined to the top of room, the lower part 
being- cooled by conduction and radiation almost en- 
tirely. It may be asked : How can a room be cooled 
by radiation? In the same way that a room is heated 
by radiation, except that in cooling a room the heat is 
radiated from the objects in the room, and not to them, 
as when heating. This gives us ample reason why a 
room should be cooled by circulating the air over 



36 



EGGS IN COLD STORAGE. 



Open side wall 
piping-. 



frozen surfaces located outside of the room, or at 
least in a position so that no radiation or conduction 
can occur. The use of insulated screens or mantles, 
as shown in Figs. 3, 4 and 5, is recommended as being- 
superior to any arrangement of open piping - ; but, of 
course, it is not equal to forced circulation, in which 
the pipes are located outside of room entirely. 

Fig. 2 shows another very common and faulty 
arrangement of piping for cooling an egg room. The 
only improvement over the arrangement shown in 
Fig. 1 is that it allows of a moderate action of gravity 




near the coils, as shown by the arrows. It is open to 
the same objection on the ground of conduction and 
radiation as No. 1, but to a lesser degree. The coils 
are placed a few inches out from the walls, to allow 
the air to circulate around the pipes freely, and to 
provide room for an accumulation of frost. The top 
of the coil should be quite close to the ceiling. If the 
coil is placed, say midway between floor and ceiling 
(unless it covers nearly the whole space), it is sure to 
result in the air becoming stratified, a warm layer of 
air in top of room resting on a colder one near floor, 
perhaps to an extent so great as to cause a difference 
of 10° F. in temperature between floor and ceiling of 
room. A case with exactlv these conditions is on 



EGGS IN COLD STORAGE. 



37 



record. Another very bad -arrangement of side wall 
piping- came to the notice of the writer recently- A 
room exceeding - fifty feet square was piped completely 
around from floor to ceiling with the exception of the 
doors. Circulation could penetrate but a compara- 
tively small portion of the space in this room, and in 
a large area of the central portion the air was conse- 
quently very foul, and mold and must were rampant. 

Fief. 3 gives u S the first primitive improvement Apron and 

° & , r \ side wall 

over open coils, and it is along step in the right direc-pip in £- 
tion, but it fails to take care of the center of the room, 



22ZZS2ZZ2ZZ2ZZZZ ZZZ22 ZZZZZZZZZZZZZZ2ZZ 




r ft (\ 



[ \ * V 



//g„<3. 



</■ 



sssss/sssss/sss/ssssssss^^-. 



especially near the ceiling. The usefulness of this 
device consists in its ability to increase the velocity, 
and consequently the volume of air passing over the 
cooling coils. The increased velocity of air causes it 
to cover a greater area, and spread toward the center 
of room further. The apron or screen used before 
the coils should be constructed of any moderately 
good non-conductor. Separating the warm and cold 
currents of air increases the draft, on the same prin- 
ciple that a fire burning in a flue creates a greater 
suction or a more rapid displacement of air than when 
burning in the open. 

Fig. 4 is simply an addition to No. 3, of a false Tnd^pronTp- 
ceiling or curtain extending well out toward the wan^pfn^? 



38 



EGGS IN COLD STORAGE. 



Gay's system 
of box coils. 



center of the room. This obliges the circulation to 
spread so as to cover a larg-e portion of the cross-sec- 
tion area of the room, as indicated by the arrows, but 
has the effect of reducing- its volume to some extent. 
This ceiling - apron should have a slant of not less than 
one foot in ten. It occupies some considerable space, 
but is richly worth it. The opening- into outer edg-e 
of apron in center of room need not exceed three 
inches in depth in most cases, and, as some space 
must be left at the top of room for air circulation 




■zzzzzz&H 



with the wall coils, without ceiling- apron, not much 
space is wasted by its addition. 

Fig-. 5 gives us an entirely different arrang-ement 
of piping-, but with essentially the arrang-ement of 
aprons shown in Fig-. 4. This is the system advo- 
cated by Mr. C. M. Gay on pag-e 106 of the Aug-ust, 
1897, number of Ice and Refrigeration, and the 
writer believes it to be the best idea for air circula- 
tion of any having- pipes directly in the room. The 
following- is quoted from Mr. Gay's description: 
"Upper pipes of box coils should be about ten inches 
below the ceiling- of the room, to prevent sweating-. 
When brine or ammonia is turned into these pipes 
(as shown in Fig-. 5), the cold air around the pipes 
seeks an outlet downward and passes between the 



BGGS IN COLD STORAGE. 



39 



false partition and the side wall of the room, thus 
displacing or pushing- along- the air in center of room, 
the cold air naturally seeking the lowest point and the 
warm air the highest point, each by reason of its rela- 
tive gravity. Thus as the cold air falls from the cool- 
ing surfaces it is replaced by the warm air from 
highest point in center of room. This secures a 
natural circulation and a dry room, there being no 
counter-currents nor tendency to precipitate moisture 
on walls or ceiling - ." 




Fig. 6 is the St. Clair or pipe loft system, which st. ciair, or 

1 • i 111 ii- PiP e l°ft 

has been applied to many remodeled overhead ice system. 
cold storages, by placing the pipes in a part of what 
formerly was the ice space, and, in some cases, using 
the original air ducts for circulation. The sketch 
here shown represents one room only, but as many as 
five or six different floors have been operated from a 
single pipe loft, using one main air duct for the down, 
and one for return air circulation, each floor having a 
connection with the mains in which the flow of air is 
regulated by gates. A better arrangement, when 
more than one floor is to be operated on this system, 
is to have independent ducts for each room, and the 
cooling coils separated likewise; then any room or 
rooms may be used for other products at any time 



40 



EGGS IN COLD STOKAGK. 



Size of 
egg rooms. 



when free of eggs. This latter arrangement, of 
course, requires more space and is slightly objection- 
able on this account. The circulation is more vigor- 
ous with this system than with any pipe-in-the-room 
system, depending on the law that the higher the 
column of air the stronger the draft, on the same 
principle that a tall chimney gives 
3 greater draft than a short one. It is, 



s 3-® s~\ 






Cs2 






^ therefore, better than any room pip- 
ing, and has the added advantage of 



V^s'SSSSSSs's' .'s'Ss's'SSs'SSSSSS. 



^ : 



y 



t / 



<: 



J 



^ 



/ 






/ 



s/sssssssssssssssssssss^. 



'ssssrstssyss 



being easily shut off from the room, when the weather 
no longer requires cooling power. The need of keep- 
ing the air of the room from contact with the frost 
on pipes will be looked into under ventilation and 
absorbents. 

Refrigerator rooms for the storage of eggs should 
not exceed. thirty or thirty-five feet in width. The 
cross-section illustrations of rooms cooled by gravity 
air circulation, which have already been illustrated, and 
the two sketches shown herewith of the arrangement 
of air distributing ducts used in two systems of forced 
circulation, are sufficient to show why a room should 
not be excessively wide as compared to its height. In 
a wide room it may be seen that the air from cold 
air ducts, in case of forced circulation, or from the 



EGGS IN COLD STORAGE. 41 

bottom of cooling" coils in case of room piping - , is 
required to pass over more eggs in its flow to the 
return air duct or false ceiling. The eggs, then, 
are not all exposed to the same drying and puri- 
fying influence, because the air as it comes from the 
cooling coils is at its maximum dryness and purity, 
and becomes impregnated with moisture and impuri- 
ties more and more as it flows through the goods. If 
the length of piles of goods is great from side to cen- 
ter of room, the eggs in top and center of room will be 
exposed to air which is much more impure and moist 
than the eggs first exposed to the flow of air directly 
from cooling coils. This applies more especially to 
the gravity systems of air circulation. With forced 
circulation, the air moves probably three or four 
times as fast as when a gravity system is used, con- 
sequently the air in top and center of room does not 
carry the amount of impurities that it does if depend- 
ing only on gravity for its motion. This fact in itself 
is a very good reason why forced circulation is supe- 
rior to any gravity system. 

It has been claimed that eggs will lose weight by ^veen'Srcuia- 
shrinkage more rapidly when stored in a room in J^"-^* 
which the air is circulated by mechanical means than 
in a room operated on the gravity air circulation prin- 
ciple. This assertion is based on the assumption 
that the air is circulated at a much higher velocity 
when forced circulation is employed, and is only 
partly true because no account is taken of humidity. 
If the humidity was the same in both cases, the claim 
would be strictly true. Every intelligent housewife 
knows that linen hung in the open air to dry, will be 
freed of moisture quicker when a strong breeze is 
blowing, than when the air is nearly still. The same 
principle applies moderately to eggs in a refrigerator 
room. With the same per cent of moisture, the more 
rapid the circulation the greater the evaporation from 
the eggs; but if the facts were known, it would be 



42 EGGS IN COLD STORAGE. 

found in every instance where trouble from excessive 
shrinkage of the egg meat was experienced, that no 
attempt was made to regulate humidity. It is as easy 
to control humidity as it is to control temperature, and 
with no bad effect on the other conditions in the storage 
room, if we go about it in the right way. Ventilation 
and the use of absorbents are agents which can be 
utilized for this purpose. 
Proportioning With a vigorous circulation of air, an egg room may 

humidity to the ° oo j 

circulation. De maintained at a humidity which would be disas- 
trous, if only a sluggish circulation was operative. 
Why? Because a brisk movement of air around the 
eggs removes the moisture and impurities as fast as 
given off by the eggs. They are not allowed to remain 
in the vicinity of the eggs to work mischief, but are 
promptly hurried off to the cooling coils or absorb- 
ents, where they are, for the most part, rendered 
harmless. This seems to explain how eggs may be 
carried sweet, and with very little evaporation, when a 
well distributed forced circulation of air is employed. 
With any gravity system, the circulation of air can- 
not be controlled, because depending on the tempera- 
ture of refrigerant flowing in the pipes for its velocity; 
and as the temperature of refrigerant is regulated to 
correspond with outside weather conditions (lower in 
warm weather and higher in cold weather) the velocity 
of circulation is not constant — being least in the cold 
weather of fall, when it is most needed. With a good 
system of forced circulation installed, the problem, 
then, is to proportion the circulation of air to the 
humidity. We might take our humidity at the degree 
which would come naturally, if no attempt were made 
to control it, and speed our blower up or down to pro- 
duce a circulation to match, but it would probably be 
best to provide a circulation which would handle a 
large volume of air at a brisk speed, and raise our 
humidity to as high a point as would be safe. Refer- 
ring to the table of correct humidity given in Chapter 



EGGS IN COLD STORAGE. 43 

II, page 23, it will be noted that an arbitrary 
percentage is given for each temperature. These 
are the most desirable percentages of air moisture 
for average conditions of circulation, as when using 
the most scientific forms of gravity air circulation 
during warm weather. When using a good system 
of forced circulation, these percentages may be in- 
creased moderately. Exactly how much will depend 
on conditions, and can be told only by trial, but it will 
be much greater in proportion at the high tempera- 
tures, ranging from 2 per cent or 3 per cent on the low, 
to 7 per cent or 8 per cent on higher temperatures. 

Before taking- up the forced circulation svstems Electricfanin 

. . egg room not 

proper, the electric fans used in so many large houses desirable, 
will be considered. These little fans are a four to 
six-bladed disk fan, from twelve to eighteen inches in 
diameter, attached directly to the shaft of a }& or 
^ -horse power electric motor. The wires supplying 
the electric current to the motor are usually con- 
nected to the socket for an ordinary incandescent 
lamp. Electric fans are usually placed on the floor 
in the back end of alleyway, or in an opening in the 
piles of goods, creating a draft of air from one ex- 
tremity of the room toward the other. As the air 
from the fan will follow a path of least resistance, the 
circulation resulting from their operation is largely 
confined to the alleyways or openings in the piles of 
stored goods — it does not penetrate through and be- 
hind the piles of eggs. It may be readily observed 
that this is of doubtful utility, and may at times lead 
to positive harm by causing a condensation of mois- 
ture upon goods as a result of the comparatively 
warm, moisture laden upper strata of air coming in 
contact with the flow of cold air from the cooling 
pipes. Electric fans have also been utilized to propel 
the air from the cooling pipes, for which purpose they 
are placed in an opening in a screen or mantle cover- 
ing the pipes, forcing the cooled air outwardly into the 



44 EGGS IN COLD STORAGE. 

room. In any other position, they are only useful as a 
"talking- point," as it is likely to impress a prospective 
customer favorably with the cooling - power of a refrig- 
erator, to allow him to stand for a few seconds in the 
breeze created by one of these high-speed fans. The 
use of electric fans has been adopted to an extent not 
warranted by the results possible to attain with them, 
and their use will no doubt be gradually discontinued 
as the fallacy of the idea becomes apparent. 
Primitive The first system of true forced circulation to con- 

forced air 

circulation. s ider is not illustrated and needs no sketch to explain 
the working of it, as there are practically no distribut- 
ing air ducts, the cold air being forced into the room 
at two or three large openings, and taken out in the 
same way. There are two prominent houses using 
an air system constructed on these lines, one having 
the cold air inlet near floor and warm air outlet near 
ceiling, the other having both cold and warm air open- 
ings near ceiling. No distribution of circulating air 
of any consequence is provided, the idea being simply 
to cool the room by forcing in air which has been 
cooled by coming in contact with cooling pipes located 
outside of the rooms. The cold air is taken in at one 
extremity of room and the warm air out at the other, 
or the cold air is taken in at ends of room and warm 
air out at center, or the reverse. This is what may 
be called a primitive form of forced circulation, and is 
quite similar to the systems of indirect steam heating 
as first employed. It needs no argument to show that 
a room equipped in this way has varying degrees of 
temperature, humidity and circulation, depending on 
the remoteness or proximity to the direct route be- 
tween cold air inlet and warm air outlet — the air mov- 
ing through the area of least resistance, which is 
usually along the center alley of room. 

Linde-British Fig. 7 shows the arrangement of ducts for air 

air-circulation a _ ... 

system. circulation used in the Linde-British air system; a a, 

cold air ducts; b b, warm air duct. This system of 



EGGS IN COLD STORAGE. 



45 



refrigeration originated in Europe, and has found 
favor to some extent on this side of the water, three 
houses known to the writer being- operated on this 
system. Mr. E. H. Johnson describes the apparatus 
used in cooling-, purifying and circulating the air on 
page 96 of the February, 1898, issue of Ice and Refrig- 
eration. This consists essentially of a tank containing 
brine, which is cooled by direct expansion piping. 
Slowly revolving in the tank, with a portion of their 
surface exposed above the surface of the brine, are 
large metallic disks. A fan causes the air to circu- 



^WvW 



^\^V\\\\^U^\\^\\\\^V\VvW\\UW ,\UUW\ ^^\^ 






\S 









«a s 



V 



/ 



TV 



J 



) 
J 






late rapidly over the brine moistened surfaces of the 
disks, and the moisture is extracted, and impurities 
and odors absorbed by the cold brine. In a modifica- 
tion of this apparatus the direct expansion coils do the 
cooling and take the place of the disks as well. The 
coils are exposed to the air circulation, and the brine is 
pumped over them in a shower, a shallow pan or tank 
being provided under coils as a reservoir and recep- 
tacle for the brine — the same brine flowing over coils 
again and again. It has been claimed for this system 
that almost any product can be stored in different 
rooms, all of which were fed by the same air circuit 
and cooling apparatus, without any injury to the most 
sensitive. A statement of this kind must first be 



46 



BGGS IN COLD STORAGE. 



Air distribu- 
tion with 
Linde-British 
system. 



proven before we can accept it. There is no doubt, 
however, but that some good features are embodied 
in above described apparatus. It is well known that 
water, and especially salt water, has a great affinity 
for impurities contained in the air, and when the air 
is circulated in contact with the brine, as in the Linde 
system, many of the gases and impurities common to 
a storage room are absorbed. That they are ab- 
sorbed to any greater extent than when the moisture 
is simply frozen on the pipe coils, the writer is not 
prepared to assert. An objection to this brine or wet 
surface air cooling is the liability of trouble when 
brine gets polluted with impurities. After some use 
the brine will no longer act as a purifier, and in this 
condition will contaminate, rather than purify, the 
air. If attended to, this trouble can be prevented by 
a periodical renewal, or by supptying a certain amount 
of fresh brine at regular intervals and allowing a 
portion to overflow. In discussing absorbents we 
will find a description of a device which seems to have 
all the advantages of the Linde method, and without 
some of the objections. 

The location of air ducts as adopted by the Linde- 
British company seems to call for some attention. It 
is evident from their location that gravity is depended 
upon for a circulation of air near floor, as both warm 
and cold air ducts are placed on ceiling of room. The 
flow of air into room is controlled by means of sliding 
gates, which are adjusted to openings placed five or 
six feet apart in the air duct. This does not provide 
a well distributed circulation, as those goods directly 
opposite openings in cold air ducts will be exposed to 
a sharp blast of air, while others get practically none. 
As a result of placing the cold air duct on ceiling, 
there will be little or no movement of the air near 
floor, when rooms are filled with goods. 

Fig. 8 shows a cross-section of a room fitted with 
a system of air ducts and false ceiling for the circu- 



EGGS IN COLD STORAGE. 



47 



lation of air in a cold storage room, which the writer 
has developed after several seasons' experiment, 
and which is regarded as very nearly theoretically 
perfect. In practical working- it gives very superior 
results, and is believed, by those who are using it, to 
be in advance of any other system now in use. By 
referring to the sketch it may be seen that the air is 
forced to cover very uniformly the entire cross-sec- 
tion area of the room — a result not possible with any 
other device. This is obtained by the use of a false 
ceiling, b b, perforated at intervals with small holes, ^^ductsjLn 

the "Cooper 
system" of 
forced air 
circulation. 




>/;sjsjj/;//,//;;;>//>;//j;;/j}l/jj/jj>j>;>/jj>jj>>jj>jj,/;//r/J 



which covers the whole ceiling of room ; and the side 
air duct, a «, perforated with small holes on top, bot- 
tom and sides. The air from cooling coils is forced 
into ducts, a «, and flows out through the perforations. 
Passing through the piles of eggs, as shown by the 
arrows, the air moves upward through the perfora- 
tions in the false ceiling, and thence through space 
between false ceiling and ceiling, to cooling coils 
again. This circulation is actuated by an exhauster, 
or blower, preferably located on the main cold air 
duct, between the cooling coils and cold air ducts, a a. 
This has a tendency to put the egg room itself under 
a slight pressure, and the coil room under a vacuum. 
In this way the air leakage from outside, if there is 



48 EGGS IN COLD STORAGE. 

any, is into the coil room, and not into the storage 
room. The perforations for outflow of air from cold 
air duct, a a, are twice as numerous on bottom as on 
the top, and some are placed in the face or side of 
duct also. The perforations are comparatively small 
holes placed quite near together, obviating - all strong 
drafts, and at the same time insuring a very pene- 
trating circulation which will not allow of any dead 
corners. The false ceiling is perforated likewise, the 
holes being most numerous through the center of 
room at farthest point from cold air ducts, and more 
widely separated as they approach sides of room 
directly Over cold air duct. If air ducts are correctly 
proportioned, the perforations properly located and of 
correct size, and eggs are piled uniformly from side 
toward center of room, the air is forced to percolate 
through the piles of eggs where its presence has such 
a salutary effect, for reasons already discussed. The 
exhauster for handling the air can be placed in almost 
any location handy to power, and the air conducted to 
it, but a more desirable arrangement is a direct con- 
nected or a direct belted electric motor. Then the 
fan may be placed advantageously to get direct and 
shorter air ducts, saving both space in the storage 
room and expense in construction. 
byuSn° f tiite ace ^ saving of space can be obtained by using this 
tin ed ci t cula " system of air circulation, amounting in some cases to 
fully 10 per cent of the total space cooled, and a sav- 
ing of 5 per cent can be had in any house, if skill and 
care are used in arranging cooling coils and air ducts. 
Where rooms are moderately high the space over a 
hallway or corridor may be utilized for cooling coils. 
As the cooling coils are located entirely outside of the 
storage room proper, the room itself can be filled 
with goods snug up to the false ceiling at the top and 
against air ducts on sides. The side ducts and false 
ceiling only occupy about two inches of space in their 
respective locations, so the space occupied by the air 



EGGS IN COLD STORAGE. 49 

system is very small. Storage men will at once ap- 
preciate that a saving- of even 5 per cent in space adds 
that much to the profits of the season's business, as 
it is as expensive to cool vacant space as it is to cool it 
when occupied by goods. 

As an objection to the forced circulation system, Cost . of 

■> J ' running- fans. 

it has been urged that the expense of running" fans 
continuously for handling the air was so large as to 
be a serious item of expense. With a well constructed 
apparatus and a large light weight fan wheel running 
at a slow speed, the air in a room containing 15,000 
cubic feet, which will store about 5,000 cases of eggs, 
may be circulated with an expenditure of effort not 
exceeding one-half a horse power. 

The selection of a fan for propelling the air is of 
considerable moment when installing an air circulat- 
ing system in a cold storage room. Fans also play an 
important part in handling air for ventilating, and the 
merits of the different kinds and forms of fans will be 
discussed under "ventilation." 



value of T N discussing - humidity and circulation, it has been 

ventilation 



CHAPTER IV. 

VENTILATION. 

1 explained how a large portion of the gases of de- 
composition and impurities of various kinds, which 
are incident to the presence of perishable products in 
cold storage, are carried by the moisture existing in 
the air, and that when this moisture is frozen on the 
cooling pipes, or absorbed by chemicals, the foul mat- 
ter is largely rendered harmless. It may now be 
noted further that even with a good circulation and 
ample moisture absorbing capacity, there will still 
be some impurities and gases, detrimental to the wel- 
fare of the stored goods, which have little or no affin- 
ity for the water vapor in the air, and consequently 
accummulate in the storage room. Ventilation is 
necessary to rid a refrigerator room of these perma- 
nent gases. The introduction of a large volume of 
fresh air is not essential, however, for the purpose of 
purifying rooms in which eggs are stored, because 
the accumulation of permanent gases in an egg room 
is quite slow, comparatively (as in rooms where well 
ripened fruit is stored); but a small supply of fresh 
air continuously, or at regular intervals, is of much 
benefit. 
Ventilation by This subject of ventilation for refrigerator rooms 

the opening- of 

doors not has been very much talked about recently, but about 
which really little is known, so far as any tangible in- 
formation is concerned. Some of the more progress- 
ive cold storage managers have given some attention 
to this part of the business, but many of the largest 
and best known houses do not ventilate their rooms at 
all, except perhaps during the winter or spring, when 
rooms are aired out for the purpose of whitewashing. 
In some cases the change of air incident to opening- 
and closing of doors, when goods are placed in stor- 
age or removed therefrom, is relied on to supply ven- 

50 



EGGS IX COLD STORAGE. 51 

tilation. This is quite inefficient, because eggs are 
mostly stored during - two or three months in the 
spring - , and removed from storage during the fall and 
winter, leaving three or four months when no fresh 
air of consequence can penetrate to the room, except 
as the doors may be opened for the purpose of taking 
the temperature of the room. Furthermore, this 
kind of ventilation during the warm weather of sum- 
mer and during a large part of the spring and autumn 
months is worse than no ventilation at all. Some stor- 
age men even take so radical a position on this matter 
of opening doors during warm weather, as to insist 
that the door shall not be opened for the purpose of 
reading the thermometer. A double window is placed 
in the door of each room, with the thermometer hang- 
ing so that it can be read from the outside without 
opening the door. While the writer has not practiced 
this method, it seems to be a good idea, and it is cer- 
tainly preferable to ventilating the room through 
doors which open to the outside air. When doors 
into rooms open into a corridor, the evil can be partly 
prevented by piping the corridor overhead, so that 
the moisture and impurities may be taken up in this 
way; but opening the door or window of a storage 
room directly to the outside air when the temperature 
outside is materially higher w T ill always result in 
more or less bad effect on the goods, as a result of the 
water vapor in the warmer incoming air being con- 
densed on same. 

Another source of ventilation similar in its results Air leakage 

into storage 

to the opening of a door or window is that resulting room - 
from the leakage of air directly into the storage room, 
through the pores and crevices in the walls around the 
doors and windows, etc. — leakage of air literally — air 
that gets in when everything is supposed to be closed. 
The amount is usually imperceptible, but is enough 
in some houses to be a serious detriment to the quality 
of work done. In small houses with large outside ex- 



52 EGGS IN COLD STORAGE. 

posure and poor insulation this air leakage is consid- 
erable, but in the big- refrigerators of several hundred 
thousand cubic feet capacity, and with thorough insu- 
lation, it is reduced to practically nothing. The loss 
of refrigeration caused by air leakage, while of some 
importance, is of small moment beside the bad effects 
resulting from the moisture and impurities brought 
in by the warm air from the outside. The value of 
prime, tight insulation, as a conserver of refrigera- 
tion, aside from a matter of keeping out the warm, 
moist air, is well enough understood not to need re- 
peating here, but a word about windows and doors is 
properly in line with the present discussion. 
Use of windows Rather than consider what might be a good way 

for egg rooms. ° o j 

of placing windows in a cold storage building, their 
use should be discouraged. Even with four or five 
separate glass, divided by air spaces, and with all 
joints set in white lead, the loss of refrigeration is 
large. It is also very difficult to fit insulation around 
the window frame so as to make a good job; and even if 
a passable job were practicable, the expense of putting 
in windows is sufficient to condemn their use. The 
increased fire exposure is of some consequence, too, 
and with the low cost of electric light, windows should 
not be thought of for cold storage work. Barring the 
small amount of heat given off, the incandescent elec- 
tric lamp is an ideal device for lighting cold storage 
rooms, as the air is not vitiated as when using gas, 
kerosene or candles. 
Joo? for e <r nson Doors which will shut tight, forming a nearly per- 
rooms. f ec t a ; r sea i 5 w ith a small amount of pressure, have 

long been wanted for cold storage rooms. Most of the 
ordinary bevel doors, either with or without packing 
on the bevel, will not shut even approximately tight; 
and in operation nine out of every ten stick and re- 
fuse to open except after many persuasive kicks and 
surges — we all know how it is. While having no in- 
terest in furthering the sale of the Stevenson door, 



EGGS IN COLD STORAGE. 53 

which will be advertised in Ice and Refrige7-ation, the 
writer believes it to be head and shoulders above any- 
thing - else in this line, and does not hesitate to recom- 
mend it to those wanting- a door which will prevent 
air leakage. The price is very reasonable, consider- 
ing the excellent material and fine work put into its 
construction. The slight additional cost over the 
common door will be quickly saved, by reason of its 
quick action — opening instantly when the lever is 
grasped. 

Having erot into the subject of air leakage, we mav Pnnci P le 

o © j o i governing' 

as well see how it is caused and why it must be air leakage. 
guarded against. It is operative from the same law 
as gravity air circulation, which was explained quite 
thoroughly in the first part of the chapter on " Circu- 
lation." When the outside air is warmer than that 
of the storage room, the air in the storage room pro- 
duces a pressure on the floor and lower part of the 
room, by reason of its greater weight, and conse- 
quently it seeks to escape there. If there are open- 
ings near the floor where the air can flow out, and 
others at the ceiling or upper part of the room, the 
air will flow in at the top and out at the bottom of the 
room. Reverse the conditions of temperature, and 
the direction of flow of air is also reversed. That is, 
when the air outside is colder than the air of the 
room, the cold air will flow into the room at the bot- 
tom and the comparatively warm air of the room out 
at the top. This action is nicely illustrated by not- 
ing the air currents in a door which is opened into a 
cold room when the temperature is very warm out- 
side. The warm air rushes in at the top of door and 
the cold air of room out at the bottom. In cold 
weather the direction of air flow will be reversed. 

Perfect inclosing walls for a cold storage room ^ r t fect°coid 
would be perfectly air tight, as they would be if lined storage room, 
with sheet metal, with soldered joints. The interior 
conditions would then be under more perfect control. 



54 EGGS IN COLD STORAGE. 

It is hardly necessary to do this (although it has 
been done in case of some old time houses), as a 
practically tight job may be had by using the right 
materials, well put on. Air leakage may not be ex- 
actly ventilation, but it is a kind of ventilation which 
has given the writer some trouble in the past, and 
does still, consequently the difficulties of operating 
a house with defective insulation and large outside 
exposure, and still turn out first-class eggs, are very 
thoroughly appreciated. 
ti"on multbe la " Methods of ventilation which are permissible 
c(Sted and when applied to the work of supplying fresh air to 
ordinary structures are generally dangerous when 
used to ventilate cold storage rooms. The problem 
in ventilating non-insulated structures is merely the 
supplying of fresh air from the outside without caus- 
ing a marked change in the temperature, and without 
creating strong drafts. Air for the ventilation of 
refrigerator rooms, during warm weather, must be 
of very nearly the same temperature and relative 
humidity as the air of the room to be ventilated, and 
free from the germs which hasten decay and cause a 
growth of fungus on the products in storage. If a 
door or window of a storage room is opened directly 
to the outside atmosphere, there will be little or no 
circulation of air into and out of the room when the 
temperature outside and in is about the same, unless 
the wind should be favorable. As we cannot ventilate 
in this way when the air outside is colder than the 
storage room, on account of freezing the eggs, and the 
introduction of fresh air, which is warmer than the 
storage room, is not permissible, for reasons already 
given, the matter reduces itself to not ventilating at 
all during warm weather (which most houses prac- 
tice), or of properly cooling and purifying the air be- 
fore forcing it into the storage room. It will bear 
repeating that it is positively bad practice to allow air 
from the outside to get into an egg room during the 



EGGS IN COLD STORAGE. o5 

summer months, also during- a large portion of the 
spring- and fall months, unless cooled and purified 
first. The fact that we cannot see the moisture de- 
posited in the form of beads of water, or floating in 
the air in the form of fog or mist, does not indicate 
that it is not present. The sling psychrometer, de- 
scribed in discussing humidity, will give an accurate 
indication of the result of this unscientific method of 
ventilating. 

Any natural means of handling air for ventilation ^^ Briggs 
is inaccurate and inoperative, or it may be positively veDtllatl0n - 
harmful, except under favorable conditions. If de- 
pending on natural gravity for ventilation it will be 
guesswork, to a greater or less extent, because de- 
pending on conditions which vary with the season, 
temperature, direction and force of the wind, etc. 
The late Robert Briggs, an authority on ventilation, 
makes a concise statement of the advantages of using 
fans for ventilation, in his " Notes on Ventilating and 
Heating."* He says: "It will not be attempted at 
this time to argue fully the advantages of the method 
of supplying air for ventilation by impulse through 
mechanical means — the superiority of forced ventila- 
tion, as it is called. This mooted question will be 
found to have been discussed, argued and combated 
on all sides in numerous publications, but the con- 
clusion of all is, that if air is wanted in any particular 
place, at any particular time, it must be put there, 
not allowed to go. Other methods will give results 
at certain times or seasons, or under certain con- 
ditions. One method will work perfectly with certain 
differences of internal and external temperature, 
while another method succeeds only. when other 
differences exist. . . . No other method than 
that of impelling air by direct means, with a fan, is 
equally independent of accidental natural conditions, 
equally efficient for a desired result, or equally 

* Proc. Am. Soc. Civil Engineers, May, 1881. 



56 



EGGS IN COLD STORAGE. 



Plenum vs. 
vacuum 
method of 
ventilation. 



Advantages of 
the plenum 
or pressure 
method. 



controllable to suit the demands of those who are 
ventilating-." 

There are two general methods, with some modifi- 
cations, for handling- air for ventilation : The plenum 
or pressure method, in which the fresh air is forced 
into the room; and the vacuum or exhaust method, in 
which the foul air is drawn out. The exhaust method 
is to be avoided for ventilating cold storage rooms, 
for reasons which we shall see presently. With this 
method, sometimes the exhaust steam from an engine 
is utilized to induce a draft of air upward from storage 
room, by heating the air in a stack or ventilation flue 
connected at its lower end with the room to be ven- 
tilated. In some cases no provision is made for an in- 
flow of fresh air, in which case it will seep in at every 
crack, crevice and pore (by reason of the partial 
vacuum created by exhausting the foul air out), bring- 
ing a load of moisture and germs of disintegration 
into the storage room. This exhaust steam method 
is no different in its result than if a fan were placed 
so as to draw the air out of the storage room under 
conditions which are otherwise the same as described 
in connection with the exhaust steam method. Should 
we provide an inlet for fresh air, through proper ab- 
sorbents, the same law would be operative, only to a 
lesser degree, as a partial Vacuum must, in any case, 
be created before the air from outside would flow into 
the room, tending to the dangerous air leakage already 
fully discussed. 

The plenum or pressure method is by far the best 
for our purpose. The air should be forced into the 
room by a fan, after first properly cooling, drying- 
and purifying it. An outlet for the escape of the foul 
gases which it is desired to be rid of, should be pro- 
vided near the floor, as these gases, by reason of 
their greater gravity, tend to accumulate in the lower 
part of the room. It will be observed that forcing* 
the fresh air in creates a pressure inside the room,. 



EGGS IN COLD STORAGE. 57 

and if there is any air leakage, it will be outwardly 
from the room — exactly the way we want it to go. 
Having- brought our subject to the point where it is 
found that the best way to ventilate is by the use of 
fans forcing the air into the storage room, we will 
determine what type of fan is best adapted to our 
needs. What is said of fans for ventilation is equally 
true if they are to be used for forced air circulation, 
described under head of circulation. 

It is admitted by a majority of experts on air mov- Disadvantages 

J ~ J r of the disk 

ing machinery that the disk or propeller wheel type type of fan. 
of fan, through which the air moves parallel to the 
axis of fan, is not efficient or desirable for work where 
the air has to travel through a series of tortuous air 
ducts, as in the forced air circulation system for cold 
storage work, or for ventilation purposes where there 
is some resistance. Where any resistance of import- 
ance is encountered, the disk fan must be driven at a 
high rate of speed, and at an immense loss of power, to 
compel it to deliver its full quota of air. Another dis- 
advantage of the disk type is the difficulty of belting 
to the shaft, or of getting power to the fan in any 
form, if it is inclosed entirely in an air duct. The disk 
type will therefore be dismissed, and the well known 
centrifugal, or peripheral discharge fan taken up. 

This type of fan draws the air in at its center Advantages of 

J r the centrifugal 

parallel to the shaft, and delivers it at right angles to^^^ n 
the shaft at the periphery or rim of the fan wheel, 
the law governing its action being the well under- 
stood centrifugal force, which is commonly illustrated 
when we see the mud fly from a buggy wheel or the 
water off a grindstone. The advantage of these fans 
over the disk type is that the centrifugal action set 
up by the rotary motion of the fan is utilized to give 
velocity to the air in its passage over the fan blades. 
In the selection of a fan for the purpose of forced cir- 
culation in the storage room, or for forcing in fresh 
air for ventilation, it should be noted that a large slow 



58 EGGS IN COLD STORAGE. 

[.'mvrconsump- runn ^ n g" fan wheel is very much more economical of 
dXrentspeeds power than a small fan running' at a high rate of speed, 
both doing the same amount of work. The loss of 
refrigeration, too, in a rapidly moving fan, is of conse- 
quence, because the air is warmed by impact with the 
blades. The proportion of power saved by the use of 
a large fan running at a slow rate of speed, rather than 
a small fan running at a high rate of speed, both de- 
livering the same amount of air, is almost phenomenal, 
and does not seem at all reasonable at first view. The 
volume of air delivered by a fan varies very nearly as 
the speed, while the power required varies about as 
the cube of the speed. That is, doubling the speed 
doubles the volume of air, while the power required is 
increased eight times. We will take a specific case. 
A 45-inch fan wheel, revolving at a speed of 200 revo- 
lutions per minute, delivers, say, 5,000 cubic feet of air 
per minute, and requires but one-quarter of a horse 
power to operate it. If the speed is increased to 400 
revolutions, the volume of air delivered will be only 
about 10,000 cubic feet, while the power required to 
drive it will be raised to two horse power. These 
figures are theoretical, but within certain limits are 
approximated in practice. 
Loss of power p or use [ n cold storage work the objection com- 

from excessive ° J 

fan weights, mon to nearly all the air moving machinery found 
listed by the manufacturers is the seemingly unnec- 
essary amount of metal used in its construction. 
The heavy weight of the fan wheels, and the large 
diameter of shaft necessitated by such weight, causes 
much friction on the journals, so that when running 
at the slow speeds desirable for cold storage work, 
more power is required to overcome the mechanical 
friction than is actually required to move the air.* 



*Having been unable to find a fan wheel well suited to the requirements of 
cold storage duty, the writer has designed and constructed a line of fan wheels 
especially for slow speeds, which are amply strong and capable of moderately 
high speeds, when necessary, but are very much lighter than most fans on the 
market, and consume proportionately less power in mechanical friction. 



EGGS IN COLD STORAGE. 59 

No doubt the high speeds necessary for some work 
have obliged the manufacturers to make their fans 
amply strong- for the highest speeds, consequently 
they are not economical for the slower speeds. It 
would not be appropriate for a person to fan himself 
with a dinner plate — it would do the work, but would 
not be economical of power. 

So far we have found out what kind of ventilation 
is not desirable, and have an inkling- of what kind 
would be desirable. The question before us now is to 
properly treat the air before introducing it into the 
storage room, so that it may be fresh — i. e., pure 
oxygen and nitrogen, without excessive moisture, 
and free from the impurities and germs which may 
contaminate the product which is being refrigerated. 

The questions referring to temperature contained Questions 

. . . relating- to 

in the letter of inquiry sent out by the writer before ventilation. 
beginning to write these articles are as follows: 

First. — What plan do you pursue in ventilating 
egg rooms? 

Second. — Under what circumstances and how often 
do you ventilate? 

Third. — How often do you consider it advisable to 
make a complete change of air? 

Outside of a bare dozen, the replies on this much- Miscellaneous 

•"■ replies to ven- 

talked-of subject were of no value whatever for our tiiation queries. 
purpose. Most of those answering do not ventilate ; 
many others get their ventilation through the opening 
of doors; some ventilate through an elevator shaft, by 
opening doors at top and bottom, etc. Only three or 
four are properly cooling and drying the air before in- 
troducing it into the egg rooms. One successful stor- 
age manager says that. "It is trouble enough to take 
microbes, bacteria, moisture, etc., out of one batch of 
air" (meaning the air in his rooms at the beginning 
of the season) , without adding to his troubles by send- 
ing in more air loaded down with the same mischief 
makers. As before pointed out, unless the air to be 



60 EGGS IN COLD STORAGE. 

used for purifying- the rooms is itself first cooled and 
purified, this man's idea is perfectly correct. 
impurities ex- The free outside air during - warm weather, espe- 

isting- in the , . » . . . . 

free outside air. cially in the vicinity of our large cities, contains, 
among- many others, germs which produce the para- 
sitic plant growth which is called mildew or mold. The 
exhalation from the lungs of the many animals and 
men who inhabit our cities, and the evaporation 
from the dust, dirt and decaying matter of various 
kinds peculiar to the street, render the air a recep- 
tacle and conveyor for impurities and germs of many 
species. The species of germs which concern us are 
active in proportion to the temperature and humidity 
of the air. In a warm atmosphere which contains 
much moisture they take root and grow rapidly, 
throwing off more germs of their kind, which impreg- 
nate the air in an increasing ratio as the humidity and 
temperature are increased. The humidity of the 
outside air is not necessarily increased with the tem- 
perature, but it is always increased to some extent, 
and as the temperature of the outside air rises we 
must necessarily be more and more careful how we 
treat and handle the air which we are to use for the 
ventilation of refrigerator rooms. 

cooling- air for it } s readilv understood why it is necessarv to cool 

ventilation. J J J 

the air before introducing it into the storage room to 
at least as low a temperature as that of the room to 
be ventilated, and some cold storage managers have 
ventilated on this basis, thinking that this was all 
that was necessary for successful ventilation. Air 
cooled only to the temperature of the storage room 
will be saturated with moisture at that temperature, 
and will be in condition to develop mold rapidly. An 
improvement on this manner of handling is to cool 
the air to be used for ventilation to a few degrees (say 
five or six) below the temperature of the storage 
room. The air will then be rendered as dry as that of 
the storage room. This is a good method of ventila- 



EGGS IN COLD STORAGE. 61 

tion, and one which the writer has practiced, but it is 
open to criticism, because of the fact that the air is 
not purified fully at the same time it is cooled and 
dried. If the air is first cooled to several degrees 
below the temperature of the room to be ventilated, 
it will be of benefit to the room, if not overdone, but 
in results will not be equal to a system to be described 
and illustrated further on in this article. 

Several houses known to the writer ventilate by inefficient 

method. 

letting- the warm outside air in at a high point of the 
ceiling, directly over cooling coils, expecting that the 
air will be properly cooled and dried before it flows 
into the room itself. The same objections are appli- 
cable to this system as are applicable to any plan of 
ventilating where the air is cooled only to the tem- 
perature of the room to be ventilated, because the 
air will be at the saturation point, and will therefore 
raise the humidity of the room, as well as introduce a 
quantity of germs and impurities. 

If we ventilate by simply cooling the air, the Sim P leair 
simplest and most effective method, as shown in 
Fig. 9, is to take the air from as high and sheltered a 
place as is accessible about the building; draw it 
down over frozen surfaces in the form of brine or 
ammonia pipes, which may be arranged anywhere 
along the wall of a room, outside of the storage en- 
tirely, if more convenient. An exhaust fan takes the 
air from the coils in the ventilating flue and forces it 
into the room to be ventilated, allowing it to escape in 
the neighborhood of the cooling coils, where it will 
mix with the air circulation, and flow into the room 
through the regular channel. It is necessary to pro- 
vide an outlet for the escape of foul air whenever 
fresh air is forced into the room. This outlet should 
be near the floor, and of about the same area as the 
inlet pipe. A steam coil may be provided beneath 
the cooling coil in ventilating flue, as shown in the 
sketch, for the purpose of melting the frost off the 



62 



EGGS IN COLD STORAGE. 




13RIMEOR 

AMMONIA 

COIL. 



STEAM 
Coi u 



FIG. 9. 



pipes. The casing- around the cooling- coil should, of 
course, be insulated moderately, as well as the pipe 



EGGS IN COLD STORAGE. 63 

leading- from it to the storage room, wherever exposed 
to the warm outside air. The size of apparatus 
necessary for this purpose need not be large, as the 
quantity of air necessary for ventilating egg rooms is 
quite small, comparatively. 

"Americus" mentions a method of washing air f or f n "ak e e mlthod. 
ventilation, in the July, 1898, number of Ice and Re- 
frigeration, which seems to have advantages. The 
idea is to draw or force air through a body of water 
or brine by immersing the intake pipe so that the air 
will bubble up through the liquid. This seems quite 
simple, but when it comes to forcing air through a 
liquid with a fan it is not so simple, as nothing short 
of an air pump will drive air through a pipe submerged 
as above described, unless the opening from pipe is 
placed quite near the surface of the liquid; in which 
case the benefit to the air is very small. Experiments 
conducted by the writer along this line were consid- 
ered failures. 

Shown in Fig. 10 is what appears as a rather com- system" warm 
plicated apparatus, but on investigation it proves to ventiiltion. 
be quite simple. There are three members to this 
system, as follows: First, The air washing tank, in 
which the air flows upward against a rain of water 
from a perforated diaphragm above, as clearly shown 
in the sketch. This not only cools the air to the tem- 
perature of the water, say 55° F. or 60° F., but it also 
takes out a large portion of the impurities of various 
kinds. From the washing tank the air is passed on, 
in a comparatively pure and cool state to be still fur- 
ther cooled. Second, The cooling tank, in which the 
air is cooled to several degrees lower temperature 
than that of the storage room. This removes the 
moisture which holds in suspension the few impuri- 
ties which may have passed the washing tank, the 
moisture being deposited on the frozen surfaces 
within the cooler. From the cooler the air is passed 
into, third, the drying box, which contains chloride of 



64 



EGGS IN COLD STORAGE. 




EGGS IN COLD STORAGE. 65 

calcium. This chemical is a well known absorber 
of moisture, what is technically known as a deliques- 
cent substance. If moisture of any account passes 
the cooler it is surely stopped in the dryer, which 
"makes assurance doubly sure," so far as delivering 
a pure, dry air is concerned. The " microbes, bac- 
teria, moisture, etc." (which influenced the gentle- 
man mentioned previously not to ventilate), are ef- 
fectually disposed of by this method. It would be a 
hardy germ, indeed, that would not succumb to such 
vigorous treatment. 

The volume of air necessarv for ventilating a Volume^ 

° require^ 

given size of egg room can only be estimated, and 
probably no two storag-e men will agree as to what is 
a correct quantity. Some say that the introduction 
of a volume of air equal to that of the room to be 
ventilated should take place each day; others twice 
each day; some even take so radical a view of it as to 
say the oftener the better if the air is properly dried 
and cooled. This is of course true enoug-h, but the 
foul gases which we can be rid of by ventilation ac- 
cumulate but slowly in an egg room, and it is probable 
that the introduction of a volume of fresh air, properly 
treated, equaling that of the egg room, twice each 
week will be ample for the purpose of keeping the 
room in good condition, and in most cases once each 
week may do nearly as well. There is much to be 
developed yet in the direction of ventilation of refrig- 
erator rooms, more particularly in the way of some 
method of knowing when a room requires ventilating. 
Perhaps Prof. Siebel or some equally bright chemist 
may be able to assist us on this point by informing - us 
what the gases are which we must dispose of, and 
indicate some simple method of determining their 
presence, and in what proportion. 

All that has been said about ventilation so far 
applies only to the ventilation of cold storag-e rooms 
when the air without is warmer than the air of the 



66 EGGS IN COLD STORAGE." 

storage room. We will now give our attention to 
another kind of ventilation, that is applicable when 
the air without is at about the same temperature as 
the storage room, or at some degree lower. This 
will be designated as cold weather ventilation, as this 
term seems to express its function perfectly. 
Natural ice . It has long- been a well understood fact that egfg-s 

cold storage in & £><=> 

cool weather. an( j other products held at about the same or a higher 
temperature take more harm in cold storage during 
the cool or cold weather of fall and winter than during- 
a long- carry through the heated term. Much has 
been said and written about why the old style over- 
head ice cold storages give such poor results during 
fall and winter, the reason assigned being lack of 
circulation, as the meltage of ice ceases when the 
cool weather comes. This is true; further, the large 
body of ice becomes an evaporating surface, and the 
dirt and impurities which are found in all natural ice, 
to a greater or less extent, have accumulated on the 
top of this ice, and the evaporation which takes place 
carries gases from this miscellaneous matter into the 
air of the storage room, with consequent bad results. 
In some houses this may be avoided by closing the 
trap doors covering circulation flues, but it is seldom 
done, and in many houses it is impossible. 

Now are we who cool our storage rooms with brine 
or ammonia pipes very much better off in this one re- 
spect than those who have these much despised over- 
head ice cold storages? Our rooms are cooled by 
frozen surfaces, on which accumulates the evaporation 
from the goods in store, which, as we have already 
plainly seen, contains much foul matter and impurities. 
Precisely as in the ice cold storages, the cooling sur- 
faces, which absorb moisture during warm weather, 
become evaporating surfaces, and give back to the air 
of the room a considerable portion of the various im- 
purities and germs which have been accumulated dur- 
ing the warm weather of summer. To make this point 



EGGS IN COLD STORAGE. 67 

more plain it may be considered thus: During- the 
period when the outside air is considerably warmer 
than the air of the storage room it is necessary to keep 
some refrigerant at work cooling the air within. This 
is usually done by circulating brine or ammonia 
through pipes, and the air of the room is circulated in 
contact with the pipes. When the outside tem- 
perature is high, more of the refrigerant must be 
circulated, or its temperature must be lowered; 
as the weather turns cooler in the fall, less re- 
frigerant, or the same amount at a higher temper- 
ature, must be circulated, and when the air with- 
out reaches the temperature of the room, the 
circulation of refrigerant must be discontinued al- 
together. When this is done the moisture on the 
cooling pipes begins to evaporate. This evaporation 
added to that which is given off by the eggs them- 
selves soon renders the air saturated with very im- 
pure and poisonous vapors, which cause the eggs to 
deteriorate very rapidly. 

The influence which the temperature of the refrig- influence of 

■*■ _ ° temperature of 

erant flowing in the cooling pipes has on the condition refrigerant in 

cooling pipes. 

of a storage room may be better understood by tak- 
ing a specific case: A room with a temperature of 
33° F. and a humidity of 70 per cent has a dew point 
(temperature at which the air precipitates moisture) 
of 25° F. Therefore any cold surface (as a pipe sur- 
face), having a temperature of 25° F. or lower, will 
attract moisture when exposed to the air of the room. 
If the pipe surfaces are heavily coated with frost, as 
they usually are as cold weather approaches, the frost 
acts as an insulator, and the refrigerant flowing in 
pipes must be at a considerably lower temperature 
than the air of the room, or no moisture is attracted. 
We have all noted how the accumulation of moisture 
on pipe coils is slower and slower as the thickness in- 
creases, until finally a limit is reached where no more 
frost will form; yet owing to the largely increased 



68 EGGS IN COLD STORAGE. 

surface the room can be kept at its normal tempera- 
ture. If pipes are badly loaded with frost, sometimes 
no absorption of moisture will take place when the 
refrigerant flowing in the coils is 10° or 15° below the 
temperature of the room. The surface exposed, to 
the air of the room, whether in the form of frost or 
otherwise, must be at or below the temperature of the 
dew point, or no moisture will be absorbed. The 
value of suitable moisture absorbing surfaces as the 
cool weather of fall and winter approaches cannot be 
overestimated, as many have found to their sorrow 
that two weeks' stay in cold storage under bad condi- 
tions in cold weather will do more harm to the eggs 
than four months during hot weather. 

The remedy for this trouble is found in keeping 
the air of the room from coming in contact with the 
poisonous frost which has been accumulated on the 
pipes during their period of duty during warm 
weather; or what is still a better way is to not allow 
the frost to accumulate on the pipes at all, by using a 
device, described further on under head of absorb- 
ents. How to keep the air from contact with the frost 
on pipes is not an easy matter, and in case of piping 
suspended directly in the room it is an impossi- 
bility. 
Evaporation With a system of screens arranged around coils, 

from frost J ° ' 

accumulated on as described in the first part of the paper on circula- 

coolingr pipes. , x 

tion, trap doors may be fitted to the openings and the 
air .circulation shut off in this way; but the simplest 
and best way is to equip the rooms with forced cir- 
culation, and locate the pipes outside of the room en- 
tirely. Then it is only a matter of shutting off the 
circulation over coils, allowing it to continue through 
a by-pass, or if the device shortly to be described is 
used, the circulation may be allowed to continue over 
coils. It seems quite clear, from what has been writ- 
ten, why a storage room gets foul quickly during cool 
weather, and also that the bad conditions. may be bet- 



EGGS IN COLD STORAGE. 69 

tered by cold weather ventilation. The harm result- 
ing- from the foul evaporation from frost on cooling- 
pipes may be obviated by not allowing contact between 
it and the air of room, but the evaporation from the 
eggs themselves must be taken up by other means 
when cooling surfaces are no longer operative. 

Bv carefullv observing conditions a storage room Handling of 

J J . ' . . . cold weather 

may nearly always be kept in prime condition during- ventilation, 
cold weather by no other means than the introduction 
of fresh outside air at as frequent intervals as right 
conditions of temperature and humidity will permit. 
It is quite safe to force in plenty of air which has 
about the same temperature and humidity as the 
room to be ventilated. There are few impurities in 
the clear, crisp air of a bright fall day, and many such 
are available for our purpose in the latitude of Min- 
nesota and New York, and a somewhat smaller num- 
ber, perhaps, in the latitude of Iowa or Ohio. It is only 
a matter of handling the free air of heaven under- 
standingly. One's impressions, however, will hardly 
do in judging what air is good to use for ventilating 
purposes. If you have a bright, clear day, or, what is 
still better, a clear, cold night, which has the appear- 
ance of being what you want, get out your sling 
psychrometer and set all guesswork aside. It is 
frequently possible to fill your egg rooms with fine, 
pure air at a temperature about the same as that of 
the room, as early as the latter part of October, if 
you are watching for the<opportunity. Provide a good 
big fan wheel, which will handle a large volume of air 
in a short time, and when conditions are right blow 
your rooms full of it. Repeat this whenever the 
weather conditions will permit. 

We may now consider cold weather ventilation Method for 

J extreme cold 

under another condition, viz.: When it is colder out- weather - 
side than inside the storage room. Whenever the out- 
side air is 8° or 10° below that of the storag-e room it 
is always perfectly safe to introduce it into the stor- 



70 KGGS IN COLD STORAGE. 

age room, after it has been first warmed to the tem- 
perature of the room to be ventilated. That is, it is 
safe so far as introducing- moisture or impurities is 
concerned. If we should ventilate in this way con- 
tinuously our humidity would be lowered to a point 
where the egg's might suffer from evaporation. It is 
necessary, therefore, that observation of the humidity 
of the room so ventilated be taken, so that this kind 
of ventilation may not be overdone. 
Manner of in- The method of getting air into the rooms under 

traducing- air. ° 

these last two systems of ventilation is of no special 
moment, except that it be under control, and we have 
already noted that the only good way of handling air 
was by the use of fans, preferably large and of light 
weight, and running at a slow speed. Where the 
forced circulation is installed, it is sometimes practi- 
cable to so connect the fans used for this purpose, 
that cold weather ventilation may be handled by them; 
but a separate fan is much better, and while seeming 
more complicated is really simpler to operate, because 
handled independently. When using an independent 
fan or when using the forced circulation fan for ven- 
tilating, the fresh air mixes with the circulation and 
is well distributed by it to various parts of the room. 
The ventilation of cold storage rooms is not a 
matter which can be safely left to such help as may 
be at hand, and if good results are to be secured " the 
boss" should see to it himself. Cold weather venti- 
lation, especially, must be handled scientifically or 
trouble may result instead of benefit. No absolute 
rules can be given for handling ventilation because of 
widely varying conditions, but if what has been writ- 
ten is read and studied carefully the subject can be 
taken up intelligently and followed out to its legiti- 
mate conclusion. 



CHAPTER V. 

ABSORBENTS. 

THE use of absorbents in cold storage rooms has^g^j^ 
been common since the industry was in its in- 
fancy; their use originating-, no doubt, from an appre- 
ciation of the fact that the air of a storage room 
quickly became too moist and impure to do the work 
of preservation perfectly. When absorbents and ven- 
tilation are applied to refrigerator rooms they prac- 
tically have one duty in common — that of purifying 
the air. Ventilation purifies by furnishing pure air 
which displaces the foul air ; absorbents by attracting 
the moisture, and with it the impurities of the storage 
room ; but where ventilation is largely for the purpose 
of forcing out the permanent gases or impurities 
which ha-ve little affinity for moisture, absorbents are 
for the purpose of taking up the moisture and the 
germs and impurities which are absorbed by it. 

Active absorbents can be made to perform duty in Prof. Nice's 

S3 r stem which 

absorbing" the moisture which is usually condensed on utilizes an 

. . absorbent. 

the cooling coils, as illustrated m one style of the 
antiquated overhead ice cold storages. If the writer 
remembers correctly, the system is called Prof. 
Nice's system. In this system the ice is supported 
above a water tight sheet iron floor which forms the 
ceiling of the storage room, the air of the room being 
cooled merely by contact with this cold metal surface, 
which is cooled by the ice above. The moisture 
given off by the eggs in storage, and that resulting 
from air leakage was taken up by an absorbent, 
chloride of calcium being the chemical mostly in 
use for this purpose. It was applied by suspend- 
ing it in pans at the ceiling of the room, or in 
some cases on the floor under the goods. Prof. 
Nice's system gave good results years ago in com- 
petition with the Jackson, Dexter, McCrea, Stevens, 
etc., systems of overhead ice cold storage, which low 

71 



72 



EGGS IN COLD STORAGE. 



Queries 
relating 1 to 
absorbents. 



Whitewash 
good wall 
coating-. 



temperatures, and the improved systems of air cir- 
culation now in use have rendered obsolete to a greater 
or less extent. Mention is made of this system, not 
as recommending - it, but to show the possibilities of 
absorbents in drying- and purifying- eg-g- rooms. 

The letter of inquiry sent out by the writer con- 
tained three questions referring- to absorbents, writ- 
ten with an idea of ascertaining- the coating- used for 
the walls of a storag-e to the greatest extent; what ab- 
sorbent was the favorite, and in what manner applied. 
The questions are as follows : 

I. Do you use an absorbent or purifier in your 
egg rooms? 

II. In what way do you use or apply them? 

III. Do you paint or whitewash? What kind and 
how often applied ? 

The most common wall coating- in use for eg-g- 
rooms is plain every-day whitewash, in various pro- 
portions of lime and salt. Several recommend one 
part of lime and one of salt. This makes a very 
good whitewash, g-iving- a firm, hard surface, but un- 
less some method of blowing- warm, dry air throug-h 
the rooms is feasible, it will dry very slowly, which 
is likely to cause it to have a mottled appearance 
instead of the pure white which gives a storag-e room 
such an attractive appearance. A better proportion 
for ordinary cold storag-e work is two parts of lime 
and one of salt. This mixture will dry faster, and 
will give a white surface which will not easily rub or 
flake off. There are many formulas for gx>od white- 
wash, some of them so complicated as to be impracti- 
cable; but plain lime and salt, with perhaps the addi- 
tion of a little Portland cement, will be g-ood enoug-h 
for our purpose. 

This last formula would then be six parts white 
lime, three parts salt, one part Portland cement. In 
preparing- this wash, proceed as follows: Slake the 
quicklime by pouring- on boiling- water, stirring- 



EGGS IN COLD STORAGE. 73 

thoroughly during the process. A half bushel of The best 

& ° r formula for 

lime is all that can be handled easily. Pour on only whitewash. 
a little water at first, adding- more as the mixture 
thickens, and do not allow the lime to become dry, or 
it will "burn" and become lumpy. When the lime is 
thoroughly slaked and reduced to the consistency of 
cream, add the salt while the mixture is still hot — the 
salt will dissolve better — adding- more water as is 
necessary to keep it to the proper consistency. The 
Portland cement should be added only to each pail- 
ful as used, as it sets if allowed to stand, and does 
not retain its tenacity. A good sized handful to each 
pailful of the wash is about right. By the addition of 
a teaspoonful of ultramarine blue to each pailful, the 
brown effect resulting from the addition of the cement 
will be neutralized. 

Storage rooms should be whitewashed during whitewashing 

~ ° storage rooms. 

cool, dry weather, with the doors open, or warm, dry 
air from a steam coil should be circulated through 
the room. This is quite a simple matter where a 
house is equipped with forced circulation. Cover the 
walls, ceiling and floor Avith a coat of whitewash 
each spring, and allow ample time for the rooms to 
air and dry out before goods are placed in them. If 
whitewash is to have a nice white appearance it must 
not be too long in drying; on the other hand, if dried 
too quickly it will flake or cleave off more readily. 
The quickest method of apptying whitewash is with 
a compressed air spray. It will make a fair job, and 
is done much quicker than by hand. 

The cold water paints, which are now quite com- cold water 
mon under various names, are good for many places 
where whitewash will not do, as on doors and in the 
corridors, or wherever the clothing may come in con- 
tact with the woodwork, or where a product is handled 
which may be injured by the flaking off of whitewash. 
Whitewash will generally rub or flake off to some 
extent, but the best of these cold water paints are 



74 



EGGS IN COLD STORAGE. 



Shellac for 
wall coating 



Lime as an 
absorbent of 
moisture and 
impurities. 



nearly as impervious as so much oil paint, and quite 
valuable for nearly all interior and some exterior 
work. Many housies use nothing else for their refrig- 
erator rooms, but the expense is not warranted, as 
whitewash will do equally well in most places. It is 
a good idea to keep some of this cold water paint on 
hand, and apply it at intervals to doors, etc., when 
they become soiled by handling. This is much better 
than to paint doors some dark color so they will not 
show soil — nothing compares with a pure white — and 
oil paint has no place about a storage room. 

Shellac is an old stand-by finish for refrigerator 
rooms, and if selected ceiling is used, it makes a very 
neat piece of work, as it brings out the natural grain 
of the wood, than which there is no more beautiful 
finish. The surface scratches easily and will look 
mussy unless renewed frequently, but there is no 
serious objection to shellac (barring the expense), as 
it is strictly odorless and waterproof. It has no puri- 
fying or disinfectant properties like lime and salt 
whitewash, in appearance is very little superior, and 
the much increased expense makes it very little used 
at present. Many other preparations are in use 
under various names, but whitewash is as good as any 
of them, with the exception previously noted. 

The two chemical absorbents in general use for 
taking up moisture and the impurities from cold 
storage rooms are chloride of calcium and lime 
(either unslaked or air slaked, or in the form of 
whitewash, as before mentioned.) Occasionally 
waste bittern from salt works is used, but the active 
principle of bittern is chloride of calcium. Ordinary 
quicklime has the property of absorbing moisture and 
impure gases from the air, and is used in very much 
the same way as chloride of calcium; that is, it is 
placed around the room on trays or pans. Lime, 
however, has very little capacity for moisture as com- 
pared with chloride of calcium, and when exposed to 



EGGS IN COLD STORAGE. 75 

the air it will simply air slake, which means that it 
will absorb moisture enough from the air to disinte- 
grate into the form of a powder. Lime in this form is 
known as air slaked lime, and is used to a large ex- 
tent in egg rooms. Air slaked lime as it comes from 
the lime house will absorb very little moisture, but it 
gives off minute particles of lime which have a good 
effect in preventing the growth of fungus, which we 
have already fully discussed. Air slaked lime is 
usually applied by spreading on the floor of the room, 
between the 2X4's (which are used at the bottom of 
each pile of eggs), to the depth of an inch or more. 
This must necessarily be done when the eggs are 
piled, and consequently its efficiency is very low 
when the cool weather of fall comes. This defect 
has been overcome by scattering fresh air slaked 
lime through the rooms so as to create a cloud of lime 
dust, but this is objected to because it musses up the 
cases. A better way of using lime is in the lump 
form — quicklime — which can be placed around the top 
of the room in trays or pans and renewed from time 
to time through the season. 

Chloride of calcium is the most vigorous absorb- ciidumasan 
ent (or drier, as it is called) which we are discussing. absorbent - 
It is the same salt of the metal calcium as common 
salt (chloride of sodium) is of the metal sodium. Both 
have a strong affinity for water, but chloride of cal- 
cium is much the more energetic of the two. Where, 
in a moist air, common salt simply attracts enough 
moisture to become damp, chloride of calcium will 
absorb enough water to lose its solid form entirely, 
uniting with'the moisture of the air to form a solution 
or brine. The strong affinity of this salt for water 
has been utilized for the purpose of drying and puri- 
fying refrigerator rooms, and in this capacity has 
been a general favorite for years. The most primi- 
tive method of applying it is to place it in a simple 
iron pan, allowing the brine to run off into a pail as 



76 EGGS IN COLD STORAGE. 

fast as formed. A better way is to support the cal- 
cium on a screen of galvanized wire, with a galvanized 
pan below for catching- the brine. This allows of a 
free circulation of air around the calcium. This 
apparatus should be suspended near the ceiling- of the 
room, one end slightly higher, to allow the brine to 
run off into a galvanized iron pail, supported at the low 
end of the pan. Galvanized iron is specified because 
black iron rusts badly when exposed to the air. 
methodof r ' s ^ s ^ better way of applying chloride of calcium, 

nde^caicium "which makes the calcium do two separate and distinct 
duties, is a method recently designed by the writer. 
It has proven itself especially valuable for use in 
rooms where the air is circulated by mechanical 
means, and in which the air is cooled by passing over 
brine pipes, through which the brine is circulating at 
a comparatively high temperature. If low brine tem- 
peratures are used in combination with the device 
about to be described, the tendency may be to dry the 
air to such an extent as to be detrimental, and ample 
pipe surface must be provided and the quantity of 
brine flowing through pipes reduced so that no ex- 
cessive drying effect will take place. The device 
consists simply of supporting a quantity of chloride 
of calcium above the cooling coils, so that the brine, 
resulting from the absorption of moisture by the cal- 
cium, will trickle down over the pipes. This effect- 
ually prevents any formation of frost on the pipes, 
and therefore keeps them at their maximum efficiency 
at all times. The air, in passing over the brine 
moistened surface of the coils is purified, and as the 
brine, after falling to the floor of the coil room, goes 
to the sewer, no contamination can take place. 

Do not in any method of using chloride of calcium 
evaporate the water from the brine and use the salt 
over again. The impurities will stay in the salt 
to .a large extent, which is quite harmful, and the 
calcium has at least lost its value as a purifier, to a 



EGGS IN COLD STORAGE. 77 

large extent. The quantity of calcium necessary Quantity of 

1 .. " ....... chloride of cal- 

depends on the conditions under which it is to be cium necessary. 

used, but in any case it is safe to use much more than 

the writer saw in use in an eastern house recently. 

A room about 30X50 and about fourteen feet high 

had the refrigerant shut off, and the room was in 

rather bad condition as to moisture, etc. In each end 

of the room a pail was placed, on which rested a wire 

screen, with perhaps ten or fifteen pounds of chloride 

of calcium on it. Electric fans were playing - on the 

calcium, which was doing- its best, but it seemed 

"like trying to dip the sea dry with a clam shell." 

This room should have had at least two drums (about 

1,200 pounds) at work in it to do it justice. 



CHAPTER VI. 



PACKAGE. 

EGGS are continually giving- off moisture from 
the time they are first dropped by the hen until 
they disintegrate, unless sealed from contact with the 
air, and we can therefore never hope to keep them in 
cold storage for several months without their losing 
some weight by evaporation. To prove that eggs 
must evaporate, the following experiment was tried 
by the writer in his early experience: An ordinary 
30-dozen egg case was lined with tin, with all joints 
carefully soldered. The eggs were then placed in 
the fillers in the tin lined case in the usual way, and 
an air tight tin cover soldered on, forming a hermeti- 
cally sealed package. After about sixty days' stay 
in an ordinary refrigerator the tins were unsoldered. 
The result noted was peculiar and startling. The 
inside of the tins was dripping wet, and very foul 
smelling, and the eggs were all rotten. This same 
experiment'was tried by a friend, working independ- 
ently and without knowledge of the writer's experi- 
ment. He used an ordinary fruit jar, with screw top 
fitting onto a rubber ring. His results were similar. 
In addition this gentleman packed some eggs in flour 
in a fruit jar, otherwise under the same conditions 
as the other experiment. The eggs packed in this way 
were all found to be in good condition when the jar 
was opened, as the moist evaporation from the eggs 
had been taken up by the flour. These experiments 
prove beyond a doubt that an egg must evaporate 
continually, and they prove further that the eggs 
must be surrounded by some medium which will 
absorb this evaporation. 

We have noted in the chapter on "Circulation," 
how the air is best circulated so as to remove the 

78 



EGGS IN COLD STORAGE. 79 

moisture and impure gases from the vicinity of the 
eggs. This must be done, otherwise the fillers and 
package containing" the eggs would shortly be in as 
bad condition as the fillers in the experiment just 
mentioned. The theory and explanation of the other 
conditions in the storage room necessary for success- 
ful egg refrigeration have also been taken up under 
the various heads. We will now look into the require- 
ments of the package containing the eggs while in 
cold storage. 

The questions contained in the letter of inquiry Queries 

j- 7l j relating to 

relating to the egg package are as follows: package. 

1. What egg package have you found to turn out 
the sweetest eggs? 

2. Have you used any kind of ventilated egg case, 
and with what results? 

3. Have you ever used open trays or racks, and 
with what results? 

As many different people have experimented with various woods 

J r r r in use f or ca ses. 

different packages, hoping to get something which 
would turn out perfectly sweet eggs, with little evap- 
oration, the replies received to the questions relating 
to packages are interesting, and many contained in- 
formation valuable as data. The favorite package is 
the ordinary 30-dozen egg case, made of white- 
wood, using the so called odorless fillers. The term 
whitewood is usually meant to include either poplar, 
cottonwood or basswood, but two or three other vari- 
eties of wood, not so well known, are designated as 
whitewood. Basswood is by some not placed in the 
whitewood list, but the best authority known to the 
writer says that basswood is as properly a whitewood 
as poplar or southern whitewood. Poplar and cotton- 
wood are most in use for storage purposes, and many 
insist that basswood is objectionable because of its 
liability to ferment or sour and cause tainted or musty 
eggs. All kinds of cases have been in storage in the 
house operated by the writer, and if all were thor- 



80 EGGS IN COLD STORAGE. 

oughly dry, no difference could be noted in the carry- 
ing- qualities of the different kinds of whitewood, and 
the preference has been for well seasoned basswood 
cases. It may be that basswood is more likely to sour 
and affect the eggs than poplar or cottonwood, but it 
is always advisable to get stock for egg cases in the 
fall and have them nailed up during the winter, allow- 
ing two or three months for the cases to season before 
the opening of the egg storing term. Some have dry 
kilns for cases, but a naturally seasoned case is to be 
preferred, as then it has a chance to deodorize as well 
as dry out. In some localities other woods are used 
for egg cases. Ash, maple, hemlock and spruce have 
been used for storage cases, generally because they 
are cheaper than whitewood in that locality. Any 
strong scented wood like pine will not do because of 
the flavor imparted to the eggs, 
■various kinds The pasteboard frames and the horizontal divid- 

oi fillers in use. * 

ing or separating boards which form for each egg an 
individual cell in the case are usually spoken of as 
fillers. For years only one grade of these was made 
— those of ordinary strawboard. When moistened by 
the evaporation from the eggs this material has a pe- 
culiar rank odor, which was taken up to some extent 
by the eggs if they were allowed to remain in the 
fillers for several months. Much of the flavor result- 
ing from a growth of fungus has been laid to the fill- 
ers, and much of the flavor resulting from fillers has 
been laid to a growth of fungus or must, but there is 
no question but what strawboard fillers are not the 
thing for cold storage use. Many kinds of fillers have 
been tried, and many ideas suggested for the improve- 
ment of cold storage eggs. A white wood pulp filler 
made its appearance some years ago, but did not 
come into general use. After being in storage a few 
months, it absorbed moisture to such an extent as to 
be very soft, and they were objectionable on this ac- 
count. A o-ood manila odorless is now on the market 



EGGS IN COLD STORAGE. 81 

which is giving* good satisfaction where tried. Ordi- 
nary strawboard fillers have been coated with various 
preparations, shellac, paraffine, whitewash, etc. Any 
substance in the nature of waterproofing might better 
be left off for the reason, as we have seen, that eggs 
must evaporate, and a waterproof filler would hold the 
moisture and not allow it to escape into the air of the 
room. It is essential to the well being of an egg that 
it should evaporate, as proven by the experiments in 
hermetically sealing, before described. Many have 
gone to the expense of transferring the eggs into dry 
fillers in the middle of the season. One season of this 
was enough for the writer. A better way is to de- 
crease the humidity of the room as the fillers become 
more and more loaded with moisture. The humidity 
may be decreased by the use of absorbents or by ven- 
tilation, as already discussed in their proper places. 
Fillers made of thin wood have been used in years 
gone by with fair success, but their manufacture has 
now been entirely discontinued. They were made of 
maple, shaved very thin, and were a prime filler so 
far as odor was concerned, but in cold storage the 
frames warp badly, and the time and eggs wasted in 
getting the eggs out of the fillers was a serious item 
against their use. As a shipping filler they were also 
a failure because of the excessive breakage. Some 
years ago an eastern company began the manufacture 
of what is known as the odorless fillers. These fill- 
ers are light brown or buff in color, and from the best 
information the writer can obtain, are composed 
largely of scrap paper stock, with some long fiber like 
manila added for strength. In the manufacture the odorless 

V ■ 1 i i i* -i fillers. 

stock is treated to a thorough washing and deodoriz- 
ing process, and the result is a filler with very little 
odor. Eggs put up in these so called odorless fillers 
and subjected to the same conditions as a similar 
grade of eggs packed in common strawboard fillers, 
generally come out of cold storage markedly superior. 



82 EGGS IN COLD STORAGE. 

A number of imitations of the original odorless filler 
are now on the market, some of them almost if not 
quite the equal of the original. Another filler which 
has given good results is the fiber filler, which is made 
from a material similar to the now well known fiber 
ware. They have very little odor, and remain hard 
and firm while in cold storage. A new odorless filler 
made from pure spruce pulp has been put on the 
market this season. This is a beautiful appearing 
filler, and unless appearances and the ordinary tests 
are deceptive will make its mark after atrial of a year 
in cold storage to prove what it can do. A ventilated 
filler made by a well known creamery supply house, 
has been suggested as an ideal filler for cold storage, 
but they are so poor mechanically that they are not 
to be thought of. The material cut away to form 
the air circulation space weakens the structure of the 
filler to such an extent as to make it dangerous as a 
shipping filler. Whatever filler is used, it should fit 
the cases, not crowding in, nor still so loose as to 
shake. If this point is looked after much breakage 
and consequent poor results from storage in the cold 
room may be avoided. 

Many styles of ventilated egg cases have been 
placed on the market in years past, but very few or 
none survive the test of time. A ventilated case, made 
by having the sides cut an inch narrower than the 
ends, has come into use, especially in one large eastern 
city. Making the sides narrower forms a space of 
half an inch on both sides of case at top and bottom, 
for the ready access of air to the interior of the case. 
This case is of very simple construction, and efficient 
in allowing a free circulation of air into the case. 
Others, however, prefer a case with sides in two 
pieces, claiming that the cracks will allow enough air 
circulation. Still others prefer the shaved or veneered 
cases with solid sides and bottom, claiming that this 
kind of a case will prevent excessive evaporation 



EGGS IN COLD STORAGE. 83 

from the eggs. As pointed out elsewhere in these 
articles, humidity and circulation have much to do 
with the evaporation from eggs; in fact, are more of 
a ruling- factor than the package, although the package 
necessarily has much to do with it. A tight package 
will allow of less evaporation than an open one. In a 
very dry room with a vigorous circulation a moder- 
ately tight package is the thing, but in a compara- 
tively moist room with poor circulation the more open 
the package the better. 

An appreciation of the poor circulation and damp storin g e re« in 

r r c r trays or racks. 

air of the overhead ice systems has caused many of 
their operators to resort to the use of open trays or 
racks for the storage of eggs. Very palatable eggs 
have been turned out in this way, but the use of trays 
in any ammonia or brine cooled room would lead to 
very excessive shrinkage of the eggs and consequent 
heavy loss in candling. On a commercial scale, too, 
the storing of eggs in trays is hardly practicable, as 
it increases the risk of breakage immensely, and the 
eggs must be transferred from the cases when re- 
ceived at the storage house, and back into cases again 
when shipped, involving much labor, and perhaps loss 
of valuable time at some stages of the market. In any 
but a very moist room, eggs stored in open trays, in 
bulk, will lose much from evaporation, and the loss 
will be proportionately higher than on an equal grade 
of eggs stored in ordinary cases and fillers. The ad- 
vantage of trays, if any, for some houses, is that con- 
tamination from fillers is avoided, and about 40 per 
cent more eggs can be stored in a given space. The 
eggs are, however, more liable to must as a result of 
moisture condensing on their surface with change of 
temperature, or on the introduction of warm goods 
into the storage room. 

The material used for forming a cushion in the 
case on top and bottom of the fillers to protect the 
eggs from contact with the case, and so that they will 



84 



EGGS IN COLD STORAGE. 



Excelsior 



cork shaving's 
for cushion. 



Packint 
in oats. 



carry in shipping-, is generally either excelsior, which 
is finely shaved wood, usually basswood, or the chips 
made in the manufacture of corks, known as cork 
shavings. The big cold storages recommend cork 
now in preference to the best excelsior. Here again 
comes a question of dryness. If the excelsior has 
been in stock for a year and stored in a dry place it is 
to be preferred to cork shavings, otherwise cork is the 
best, because we know cork is always dry. Cork 
makes a very poor cushion as compared to excelsior; 
it is liable to shift in the case, leaving one side without 
protection. As a matter of cost too, cork is much 
more expensive than excelsior. A company known 
to the writer manufacture a beautiful grade of bass- 
wood excelsior, which is always fairly dry when re- 
ceived, and makes as fine a cushion for protecting the 
eggs as can be desired. If people want cork in 
their cases they can have it by paying the price, but 
dry, seasoned, fine basswood excelsior is better, for 
reasons stated. 

Eggs have been packed in oats for years, but the 
practice has gradually fallen off, as eggs stored in 
cases from the best cold storage houses have been im- 
proved in quality from year to year. Oats, if dry, 
will absorb moisture from the egg quite rapidly, and 
are objectionable on this account. If the oats are not 
dry the germs of mold are developed rapidly, and as 
the moisture is given off by the eggs, the mold will 
grow, causing the eggs to become "musty." There- 
fore the main difficulty in using oats as packing for 
eggs in cold storage is to have them at the correct de- 
gree of dryness. It is almost impossible to have them 
in the same condition at all times. Oats have also been 
used in cases inside the fillers, that is, the layers of 
eggs are first put into the filler; then the oats are sifted 
into the spaces around the eggs flush with the top of 
the filler. This is repeated through the whole case; 
all the space in the case not occupied by the eggs 



EGGS IN COLD STORAGE. 85 

being- filled with oats, excepting- the small space taken 
by the fillers themselves, the object being, of course, 
to prevent the "fillers taste." 

At intervals we read of some method of preserving- Complicated 

■*■ _ and obsolete 

eggs, which is said to be sure to supersede ordi- methods of pre- 

00 *■ serving' egg's. 

nary cold storage for the good keeping of eggs. A 
scheme was tried on a large scale somewhere across 
the water, in which the eggs were suspended in racks 
in a cold room — the racks being turned at regular in- 
tervals by automatic machinery to keep the eggs from 
spoiling, that is, to keep the yolk from attaching to 
the shell. A low temperature will prevent this, as 
pointed out in the chapter on temperature, and why 
a man should waste good energy inventing such a ma- 
chine is passing all comprehension. The quantity of 
various chemical preparations manufactured and sold 
for egg pickling or preserving is even now quite large, 
but the high class stock now turned out by the best 
equipped cold storage houses has made any other 
method of preserving eggs at the present day almost 
entirely obsolete. 



CHAPTER VII. 



REMARKS. 



some "dontv 'HP v HEREis along string- of "don'ts " in regard to 
handfing C ^d g ' J- packing-, handling- and storing- eggs which might 
be put down, but the writer will be content with a few 
of the simpler and most useful ones. To start with, 
don't store very dirty, stained, cracked, small or bad 
appearing eggs of any description. Have your grade 
as uniform as possible. The culled eggs will usually 
bring within two cents of the market price, and it 
pays better to let them go at a loss rather than try to 
store them. Don't use fillers and cases the second 
time; they are more likely to cause musty eggs than 
new ones. Don't ship eggs in cold cars, or set eggs 
which are intended for storage in ice boxes. In ship- 
ping eggs from the producing section to the storage 
house in refrigerator cars, no ice should be put in the 
bunkers, because if the eggs are cooled down and ar- 
rive at their destination during warm or humid 
weather they will collect moisture or "sweat," and an 
incipient growth of mold will result. Don't use heavy 
strawboard fillers for storing eggs. If "the best way 
to improve on a good thing is to have more of it," then 
the best way to improve on a poor thing is to have less 
of it; and if strawboard fillers are objectionable, then 
the thinner they are the better, because less of the 
material is present to flavor the eggs. Further, the 
thin board fillers are more porous, and allow of afreer 
circulation of air around the &gg. As already stated, 
odorless fillers are better than any strawboard fillers. 
Don't use freshly cut excelsior. It should be stored 
in a dry place at least six months. Use no other kind 
but basswood or whitewood. Don't store your cases, 
fillers or excelsior in a basement or any damp place. 
Don't run warm goods into a room containing goods 

86 



EGGS IN COLD STORAGE. 87 

already cooled when it can be avoided. For this rea- 
son very large rooms are not to be desired. A small 
room may be quickly filled with goods and closed until 
goods begin to go out in the fall. If a larg-e room is 
used it may require several weeks to fill completely, 
during which time the fluctuation of temperature is 
at times excessive, causing condensation on the goods, 
which will propagate must quickly. 

To illustrate: We will suppose the egg room partly Don't put 

1 x °° l j warm eggs into 

filled with goods cooled to a temperature of 30° F. Sev-acoidroom 

L along with eggs 

eral cars of eggs at a temperature of, say, 70° F. are run already cooled. 
into the same room. The new arrivals, in cooling to 
the low temperature, give off large quantities of vapor 
from cases, fillers and the eggs themselves, the vapor 
condensing, of course, on any object in the room which 
is below the dew point of the air from which the warm 
goods came. This may seem like a finely spun theory, 
but the writer has had some experience which amply 
justifies this explanation. That the moist vapor given 
off by the warm goods does not show in the form of 
beads of water, or fog, or steam, is no proof that it 
does not exist. If the extremes of temperature are 
as great as 25° F. condensation will occur on nine 
days in ten during the egg storing season. The goods 
already in storage are raised in temperature materi- 
ally by placing in warm goods, which is harmful to 
some degree. The logical deduction from above 
seems to indicate that warm goods should not be 
placed in a room with goods which have been reduced 
to the carrying temperature. A separate room 
should be provided for this purpose near the receiv- 
ing room in which the goods coming in warm may be 
cooled to very near the temperature of permanent 
storage room. This is a refinement which small 
houses cannot afford, and which most of the larger 
ones do not have. 

If you wish to progress compare your results with 
those of others. Don't say: "My eggs are as good as 



8<5 EGGS IN COLD STORAGE. 

fresh' 1 ; test carefully from time to time through the 
season, and compare quality with those from other 
houses. 

In the foregoing - articles I have given my own im- 
pressions combined with the data and experience re- 
ceived from others; but I do not care to be held abso- 
lutely to any of the statements made, and reserve the 
right to progress with the rest of you, and do not 
consider myself bound by any hard and fast rule. 

It should be positively understood that a mere 
theoretical information on this subject is of only lim- 
ited assistance; and those who undertake new work 
are advised to put a man in charge who has had expe- 
rience with the product which it is proposed to handle 
in storage, as well as acquaintance with the mechanical 
details of the plant. 



ADVERTISEMENTS 




Testing Eggs by Electric Light. 

This picture is from a photograph of a couple of candling' booths, designed by the 
author of "Eggs in Cold Storage." Each candler works by herself in a small room 
closed on three sides by matched stuff, and on the fourth or front side bs' a heavy 
curtain to keep out the light. These curtains are seen pushed back in the picture, so 
that the interior of the booth may be photographed. The white boxes in the center of 
the booths are candling boxes. The\' are pierced with two holes, and have an electric 
lig'ht suspended inside A shelf, showing' in the picture, runs around three sides of the 
booth at a convenient height above the cases, for supporting fillers, dividing boards, 
nails, hatchet, etc. The barrel is for the litter of various kinds (old newspapers, etc.) 
which always accompany country packed, eggs. The pail just above the barrel is for 
rotten eggs. Cork shavings ma3 r be seen in the box between the two booths. The 
advantage of each candler working independently will be appreciated by all familiar 
with the work. The concise arrangement of this style booth makes a great saving in 
space as compared to the ordinary candling room. 



MADISON COOPER, 

Refrigerating Engineer, 

Minneapolis, Minn., 

410 First St., N. 

Designer of " The Cooper Systems," Gravity Brine Circulation ; 

Positive Fan Ventilation and Forced Air Circulation. 
Plans, Estimates and Personal Supervision of Construction. 

Expert on the Successful Refrigeration of Perishable Products. 



ADVERTISEMENTS 



NEW YORK 

OFFICE, 

85 CHAMBERS 

STREET 




LONDON 

OFFICE 

106 HATTON 

GARDEN, E. C. 



41 ELIZABETH STREET 

MAKERS OF 




FOR ALL 

REFRIGERATING 
ICE MAKING and 
COLD STORAGE 

PURPOSES 
THERMOMETER FOR 

BRINE TANKS, PUMPS 

AMMONIA PIPES 

and STILLS 

INSULATED BRINE PIPE 

THERMOMETER 
FREE FROM FROST 

CERTIFIED EGG ROOM 

THERMOMETER, ETC. 



Fid. A-4. 



mrite for Refrigerating Catalogue 




Fig. 31. 



ADVERTISEMENTS 



THE WHITLOCK COIL PIPE CO 

ELMWOOD, CONN., I. S. A. 



Pipe Coils of everj^ descrip- 
tion — for all purposes — made ,. 
of all kinds of metal, tubing o 
or pipe. Manifolds and Re- 
ceivers — Quarter Turns and 
Return Bends. 



Manufacturers 
of... 




Wrought Iron Ammonia Coils 



Daily capacity, 8,000 to 10,000 
feet. Range, Y% to 4-inch pipe 
or tube. First-class workman- 
ship, prompt delivery. 



For Ice and Refrigeration Machines — 
by the latest improved process, from 
wrought iron pipe of the finest quality. 
Tested by hydraulic or air pressure. 



THE WHITLOCK COIL PIPE CO. 

ELMWOOD, CONN., U. 5. A. 

Cable Address, "Whitlock," Hartford 

Directory Code. 

Telephone Address, Elmwood 



Carbonic -Anhydride System 



ECONOMY 




SAFETY 



ODORLESS 



NON-CORROSIVE 



This is the COMING ICE AND REFRIGERATING MACHINE ; applicable to all com 
mercial purposes. Superiority established in numerous trials. Uses a harmless but 
most efficient gas, and is equipped with reliable safety devices. Our Catalogue explains 
all theoreticarand technical details. If you are interested, write to 

Kroeschell Bros. Ice Machine Co. 

29=39 ERIE STREET, CHICAGO, ILL. 



ADVKKTISKMENTS 



4 The Cooper System" 

Forced Air Circulation. 



UPliNlUINo WHO KNOW. 

F. R. NOONAN & CO.— Wholesale Butter and Eggs 
and Cold Storage, Minneapolis, Minn. 

"We have used your Forced Air Circulation in our Egg Rooms for 
the past two years, and are fully convinced that it is the only proper 
way to carry eggs in cold storage." 



E. F. DUDLEY— Wholesale Butter and Eggs, 
Owosso, Mich. 

"I consider your Forced Air Circulation for Egg Rooms very 
fine. It gives the rooms bright, clear, fresh-smelling air and very 
even temperature; much better in this respect than the more com- 
mon method of simply taking in fanned air at one or two openings 
in a room — to say nothing of the behind-time systems of natural 
draft." 

PORTLAND ICE WORKS and PORTLAND ARTI- 
FICIAL ICE CO., Portland, Ore. 

"I placed eight registered thermometers in different locations 
in this large Egg Room. I never witnessed such a remarkable, 
even scale of temperatures. With your system of Air Circulation 
there is not a spot in this room where there is a difference of one- 
tenth of a degree. The temperature is easily controlled. It can be 
placed at any point desired, and held there without risk of any 
kind." 

W. E. HARRIS, 

Sup't Mechanical Department. 

MADISON COOPER, Designer, 

Minneapolis, Minn. 



Compressed Air 

Published monthly. Now in its fourth year. The only periodical devoted exclu- 
sively to this subject. It is both theoretical and practical, progressive and up-to-date. 
Subscription, $1.00 a year. Foreign, $1.50. Send for sample copy. 

Compressed Air> 26 Cortlandt St., N. Y. 



ADVERTISEMENTS 



Eugene T. Skinkle 

("THE BOY") 

Tfce flftaking anb 
IRefrigeratinQ Engineer 



Rooms 30 and 32 

177 LA SALLE STREET 

CHICAGO, ILL. 



Plans and specifications for Ice Making and Refrig- 
erating establishments, and consultation in relation to 
buildings, machinery and apparatus, alterations and 
repairs. 

IReferences: 

BIRMINGHAM ICE FACTORY CO., Birmingham, Ala. 
CITY ICE MANUFACTURING CO., Chicago, 111. 
LITTLE ROCK ICE CO., Little Rock, Ark. 

EAST ST. LOUIS ICE AND COLD STORAGE CO., E. St. Louis, 111. 
KINGSTON ICE MAKING CO., Limited, Kingston, Jamaica, West Indies 
GEO. CHALLONER'S SONS CO., Oshkosh, Wis. 

EL RENO ICE AND COAL CO., El Reno, Okl. 
MONROE CATERING CO., Chicago, 111. 

KING'S RESTAURANT, Chicago, 111. 

AMERICAN RESTAURANT, Chicago, 111. 
And Many Others. 



flee finmking anfc IRefriaeratinG Supplies 



ADVERTISEMENTS 



The Recognized Authority in all 
Cold Storage Matters. 




h|GA6° (^'Sa!ev/|TorkI 



A MONTHLY REVIEW OF THE ICE. ICE MAKING, REFRIGERATING, COLD STORAGE AND 

KINDRED TRADES. 



SUBSCRIPTION PRICE 

In United States, Canada and Mexico, 

In all other countries, ...... 

PAYABLE IN ADVANCE. 



$2.00 per year 
3.00 per year 



H. 5. RICH & CO. 



206 Broadway, NEW YORK 



PUBLISHERS 



177 La Salle Street, CHICAGO 



A/so publishers of the following Standard Books on Cold Storage, ire Making 
a iid Refrigeration: 

Gompeno of /Ifoecbanical IRefrigeratlon 

By Prof. J. E. SIEBEL. 
Price. Prepaid, Cloth, $3.00; Morocco. 83.50. 
The 011I3' work treating- of all the various branches of theoretical and applied 
refrigeration, and will be found to contain a large amount of information which would be 
looked for in vain elsewhere. 

practical lice Making ano IRcfrigecating 

By EUGENE T. SKINKLE. 
Price, Prepaid, Cloth, 81.50; Morocco 82.00. 
Every branch of ice making and refrigerating is handled.in this work, with a view 
to setting out the best and most economical practice in the construction and operation 
of the plant. 

Ifnoicattna tbc IRefrigerating /Ifcacbine 

By GARDNER T. VOORHEES. 
Price. Prepaid. Cloth, 81.00; Morocco, $1 50. 
Treats of the application of the indicator to the ammonia compressor and steam 
engine, with practical instructions relating to the construction and use of the indicator 
and reading and computing indicator cards. 



ADVERTISEMENTS 

HEADQUARTERS FOR 




«► 



Prime white, full strength, packed in 600-pound iron drums. 
Representing- the largest output in the country, we are in condi- 
tion to name interesting- prices for car lots or less quantities. 

PETER VAN SCHAACK & SONS 

138-140 LAKE STREET, CHICAGO. 



ACCURATE THERMOMETERS. 

Thermometers bought from us at one time give the same result 

as thermometers bought from us at 

any other time. 

Prof. Marvin's Sling Psychrometer 

for the exact determination of moisture in the air, is made 
with the utmost care and is the best of its class. 

ALL THERMOMETERS MADE BY US ARE 
GRADUATED AND ETCHED ON THE STEM. . 

Send for a Sample of oar Storage Room Thermometer. 
Price, $1.00 each. 

SCHNEIDER BROS. 

265 Greene Street.. ..NEW YORK 



Makers to.. .UNITED STATES WEATHER BUREAU. 

SIGNAL CORPS UNITED STATES ARMY. 
FISH COMMISSION. 



ADVERTISEMENTS 



25° BEItOHl ZERO BRlflE 

OBTAINED WITH THE 

PoHTIFEX-fiEflDRlCK 



MACHINE 



FEATURES: 

MAXIMUM CAPACITY SIMPLICITY 

HIGHEST ECONOMY DURABILITY 

SPECIALLY ADAPTED FOR VENTILATING SYSTEMS 



FOR PARTICULARS ADDRESS 



The Cfl^BONDflkE JVLachiNe Company 



CARBONDALE, PA. 



NEW YORK OFFICE, 1012 HAVEMEYER BUILDING. 



NONPAREIL CORK 



the Ideal 
Insulation 



Sheets for 

Walls 

Rooms 

Ceilings. 

3-feet 

Sections for 

Steam, Brine 

Ammonia 

and 

Water Pipes 



F 3 A TT E> N T E> IZ> . 



USE CORK! says"THEBOY" 
in his Practical Ice Making and Refrigerating, 
page 164. 

"In the selection of insulating substances 
their power to withstand moisture plays an im- 
portant part in most cases. In this respect Cork 
is a very desirable material," says Professor 
J. E. Siebel in his Compend of Mechanical Refrig- 
eration, page 155. 



The Nonpareil Cork Mfg* Co* 

28 QUEEN STREET, 92 WEST BROADWAY, 

LONDON, E. O, ENG. NEW YORK, N. Y. 



ADVERTISEMENTS 



Tee and Refrigerating machines 



FOR CREAMERIES AND 
PRODUCE DEALERS 



Refrigerating Machines are rapidly taking the place of 
ice for refrigerating purposes. A lower temperature can 
be secured. The cold is absolutely dry. It will pay you to 
investigate and get estimate on plant. 



SIMPLE 
STRONG 
COMPACT 
DURABLE 




LARGEST 
EFFICIENCY 
POSSIBLE BE- 
CAUSE ABSO- 
LUTELY NO 
CLEARANCE 



THE ONLY SMALL MACHINES OF DUPLEX TYPE 

EQUIVALENT TO TWO INDEPENDENT MACHINES. ONE 
ALWAYS IN RESERVE AS PROTECTION AGAINST 
LOSS FROM' STOPPAGES AND BREAK DOWNS. 

Small Plants front 2 to 10 Cons Refrigerating Capacity Our Specialty 

Estimates Cheerfully and Promptly Given. 



Write for our Handsomely Illustrated Booklet named 4i Cold A/aA-iz/o-." 



Creamery Package Manfg. Co. 

1, 3 and 5 WEST WASHINGTON STREET . 

CHICAGO, ILL. 



Jlk 14 1899 



ADVERTISEMENTS 



Doors for Cold Storage 
and Ice Rooms — 




These doors have self-acting- fasteners, and unfasten 
from either side as easily as a thumb latch. They 
include frame and hardware, all fitted up complete 
in one structure, adjusted ready to push in place, 
screw fast and use. 

They are made with 
sill as cut herewith, 
with beveled thresh- 
old attached to 
frame, or to go on a 
flush floor with nei- 
ther sill nor thresh- 
old. Others have 
trap for overhead 
track, rigged com- 
plete to rise in ad- 
vance of door so it 
cannot be smashed 
out by the trolley. 

They are Yellow Pine with Spruce back, or all 
Spruce or all Yellow Pine. 

Trap doors, to pass ice into store rooms, are opened 
and closed by the passing ice. They are cush- 
ioned, and there is no knocking, nor any rush of 
air in either direction. 

t^* t<?* «^* t&* t^r* t£T* t£r* t£r* 

Complete information, diagrams and illustrations 
in our circulars. 



A perfect seal at top, 
bottom ' and corners, 
where others always 
fail 

Cannot stick, leak, 
nor wear out. 

Works from either 
side, gives clear door- 
way, includes lock. 

Made also for flush 
floor 

STEVENSON CO., Ltd. 

BUILDERS MILL WORK 

1603=29 W. Third St. 

CHESTER, PEA'A'A. 




MB -17.8 




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